Merge 0fac198def ("Merge tag 'fs.idmapped.overlay.acl.v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux") into android-mainline

Steps on the way to 6.0-rc1

Resolves merge conflicts in:
	fs/overlayfs/inode.c

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I382394f56b40b1dd317004e1c42a51ebc11a09bb

Documentation/filesystems/overlayfs.rst

@@ -490,10 +490,6 @@ overlay filesystem and the value of st_ino for filesystem objects may not be
 persistent and could change even while the overlay filesystem is mounted, as
 summarized in the `Inode properties`_ table above.
 
-4) "idmapped mounts"
-When the upper or lower layers are idmapped mounts overlayfs will be mounted
-without support for POSIX Access Control Lists (ACLs). This limitation will
-eventually be lifted.
 
 Changes to underlying filesystems
 ---------------------------------

MAINTAINERS

@@ -9620,6 +9620,7 @@ F:	drivers/input/misc/ideapad_slidebar.c
 
 IDMAPPED MOUNTS
 M:	Christian Brauner <brauner@kernel.org>
+M:	Seth Forshee <sforshee@kernel.org>
 L:	linux-fsdevel@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git

fs/ksmbd/vfs.c

@@ -963,7 +963,7 @@ ssize_t ksmbd_vfs_getxattr(struct user_namespace *user_ns,
  */
 int ksmbd_vfs_setxattr(struct user_namespace *user_ns,
 		       struct dentry *dentry, const char *attr_name,
-		       const void *attr_value, size_t attr_size, int flags)
+		       void *attr_value, size_t attr_size, int flags)
 {
 	int err;
 

fs/ksmbd/vfs.h

@@ -109,7 +109,7 @@ ssize_t ksmbd_vfs_casexattr_len(struct user_namespace *user_ns,
 				int attr_name_len);
 int ksmbd_vfs_setxattr(struct user_namespace *user_ns,
 		       struct dentry *dentry, const char *attr_name,
-		       const void *attr_value, size_t attr_size, int flags);
+		       void *attr_value, size_t attr_size, int flags);
 int ksmbd_vfs_xattr_stream_name(char *stream_name, char **xattr_stream_name,
 				size_t *xattr_stream_name_size, int s_type);
 int ksmbd_vfs_remove_xattr(struct user_namespace *user_ns,

fs/overlayfs/inode.c

@@ -454,23 +454,94 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 	return res;
 }
 
+/*
+ * Apply the idmapping of the layer to POSIX ACLs. The caller must pass a clone
+ * of the POSIX ACLs retrieved from the lower layer to this function to not
+ * alter the POSIX ACLs for the underlying filesystem.
+ */
+static void ovl_idmap_posix_acl(struct user_namespace *mnt_userns,
+				struct posix_acl *acl)
+{
+	for (unsigned int i = 0; i < acl->a_count; i++) {
+		vfsuid_t vfsuid;
+		vfsgid_t vfsgid;
+
+		struct posix_acl_entry *e = &acl->a_entries[i];
+		switch (e->e_tag) {
+		case ACL_USER:
+			vfsuid = make_vfsuid(mnt_userns, &init_user_ns, e->e_uid);
+			e->e_uid = vfsuid_into_kuid(vfsuid);
+			break;
+		case ACL_GROUP:
+			vfsgid = make_vfsgid(mnt_userns, &init_user_ns, e->e_gid);
+			e->e_gid = vfsgid_into_kgid(vfsgid);
+			break;
+		}
+	}
+}
+
+/*
+ * When the relevant layer is an idmapped mount we need to take the idmapping
+ * of the layer into account and translate any ACL_{GROUP,USER} values
+ * according to the idmapped mount.
+ *
+ * We cannot alter the ACLs returned from the relevant layer as that would
+ * alter the cached values filesystem wide for the lower filesystem. Instead we
+ * can clone the ACLs and then apply the relevant idmapping of the layer.
+ *
+ * This is obviously only relevant when idmapped layers are used.
+ */
 struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu)
 {
 	struct inode *realinode = ovl_inode_real(inode);
-	const struct cred *old_cred;
-	struct posix_acl *acl;
+	struct posix_acl *acl, *clone;
+	struct path realpath;
 
 	if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode))
 		return NULL;
 
+	/* Careful in RCU walk mode */
+	ovl_i_path_real(inode, &realpath);
+	if (!realpath.dentry) {
+		WARN_ON(!rcu);
+		return ERR_PTR(-ECHILD);
+	}
+
+	if (rcu) {
+		acl = get_cached_acl_rcu(realinode, type);
+	} else {
+		const struct cred *old_cred;
+
+		old_cred = ovl_override_creds(inode->i_sb);
+		acl = get_acl(realinode, type);
+		ovl_revert_creds(inode->i_sb, old_cred);
+	}
+	/*
+	 * If there are no POSIX ACLs, or we encountered an error,
+	 * or the layer isn't idmapped we don't need to do anything.
+	 */
+	if (!is_idmapped_mnt(realpath.mnt) || IS_ERR_OR_NULL(acl))
+		return acl;
+
+	/*
+	 * We only get here if the layer is idmapped. So drop out of RCU path
+	 * walk so we can clone the ACLs. There's no need to release the ACLs
+	 * since get_cached_acl_rcu() doesn't take a reference on the ACLs.
+	 */
 	if (rcu)
-		return get_cached_acl_rcu(realinode, type);
+		return ERR_PTR(-ECHILD);
 
-	old_cred = ovl_override_creds(inode->i_sb);
-	acl = get_acl(realinode, type);
-	ovl_revert_creds(inode->i_sb, old_cred);
-
-	return acl;
+	clone = posix_acl_clone(acl, GFP_KERNEL);
+	if (!clone)
+		clone = ERR_PTR(-ENOMEM);
+	else
+		ovl_idmap_posix_acl(mnt_user_ns(realpath.mnt), clone);
+	/*
+	 * Since we're not in RCU path walk we always need to release the
+	 * original ACLs.
+	 */
+	posix_acl_release(acl);
+	return clone;
 }
 
 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags)

fs/overlayfs/overlayfs.h

@@ -249,7 +249,8 @@ static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
 				  const char *name, const void *value,
 				  size_t size, int flags)
 {
-	int err = vfs_setxattr(ovl_upper_mnt_userns(ofs), dentry, name, value, size, flags);
+	int err = vfs_setxattr(ovl_upper_mnt_userns(ofs), dentry, name,
+			       (void *)value, size, flags);
 
 	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
 		 dentry, name, min((int)size, 48), value, size, flags, err);

fs/overlayfs/super.c

@@ -1024,9 +1024,6 @@ ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
 			struct dentry *dentry, struct inode *inode,
 			const char *name, void *buffer, size_t size)
 {
-	if (!IS_POSIXACL(inode))
-		return -EOPNOTSUPP;
-
 	return ovl_xattr_get(dentry, inode, handler->name, buffer, size);
 }
 
@@ -1042,9 +1039,6 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 	struct posix_acl *acl = NULL;
 	int err;
 
-	if (!IS_POSIXACL(inode))
-		return -EOPNOTSUPP;
-
 	/* Check that everything is OK before copy-up */
 	if (value) {
 		acl = posix_acl_from_xattr(&init_user_ns, value, size);
@@ -1987,20 +1981,6 @@ static struct dentry *ovl_get_root(struct super_block *sb,
 	return root;
 }
 
-static bool ovl_has_idmapped_layers(struct ovl_fs *ofs)
-{
-
-	unsigned int i;
-	const struct vfsmount *mnt;
-
-	for (i = 0; i < ofs->numlayer; i++) {
-		mnt = ofs->layers[i].mnt;
-		if (mnt && is_idmapped_mnt(mnt))
-			return true;
-	}
-	return false;
-}
-
 static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct path upperpath = { };
@@ -2170,10 +2150,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers :
 		ovl_trusted_xattr_handlers;
 	sb->s_fs_info = ofs;
-	if (ovl_has_idmapped_layers(ofs))
-		pr_warn("POSIX ACLs are not yet supported with idmapped layers, mounting without ACL support.\n");
-	else
-		sb->s_flags |= SB_POSIXACL;
+	sb->s_flags |= SB_POSIXACL;
 	sb->s_iflags |= SB_I_SKIP_SYNC;
 
 	err = -ENOMEM;

fs/posix_acl.c

@@ -199,7 +199,7 @@ EXPORT_SYMBOL(posix_acl_alloc);
 /*
  * Clone an ACL.
  */
-static struct posix_acl *
+struct posix_acl *
 posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
 {
 	struct posix_acl *clone = NULL;
@@ -213,6 +213,7 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
 	}
 	return clone;
 }
+EXPORT_SYMBOL_GPL(posix_acl_clone);
 
 /*
  * Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
@@ -361,8 +362,8 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode,
 {
 	const struct posix_acl_entry *pa, *pe, *mask_obj;
 	int found = 0;
-	kuid_t uid;
-	kgid_t gid;
+	vfsuid_t vfsuid;
+	vfsgid_t vfsgid;
 
 	want &= MAY_READ | MAY_WRITE | MAY_EXEC;
 
@@ -370,30 +371,28 @@ posix_acl_permission(struct user_namespace *mnt_userns, struct inode *inode,
                 switch(pa->e_tag) {
                         case ACL_USER_OBJ:
 				/* (May have been checked already) */
-				uid = i_uid_into_mnt(mnt_userns, inode);
-				if (uid_eq(uid, current_fsuid()))
+				vfsuid = i_uid_into_vfsuid(mnt_userns, inode);
+				if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
                                         goto check_perm;
                                 break;
                         case ACL_USER:
-				uid = mapped_kuid_fs(mnt_userns,
-						     i_user_ns(inode),
+				vfsuid = make_vfsuid(mnt_userns, &init_user_ns,
 						     pa->e_uid);
-				if (uid_eq(uid, current_fsuid()))
+				if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
                                         goto mask;
 				break;
                         case ACL_GROUP_OBJ:
-				gid = i_gid_into_mnt(mnt_userns, inode);
-				if (in_group_p(gid)) {
+				vfsgid = i_gid_into_vfsgid(mnt_userns, inode);
+				if (vfsgid_in_group_p(vfsgid)) {
 					found = 1;
 					if ((pa->e_perm & want) == want)
 						goto mask;
                                 }
 				break;
                         case ACL_GROUP:
-				gid = mapped_kgid_fs(mnt_userns,
-						     i_user_ns(inode),
+				vfsgid = make_vfsgid(mnt_userns, &init_user_ns,
 						     pa->e_gid);
-				if (in_group_p(gid)) {
+				if (vfsgid_in_group_p(vfsgid)) {
 					found = 1;
 					if ((pa->e_perm & want) == want)
 						goto mask;
@@ -699,7 +698,7 @@ int posix_acl_update_mode(struct user_namespace *mnt_userns,
 		return error;
 	if (error == 0)
 		*acl = NULL;
-	if (!in_group_p(i_gid_into_mnt(mnt_userns, inode)) &&
+	if (!vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)) &&
 	    !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID))
 		mode &= ~S_ISGID;
 	*mode_p = mode;
@@ -710,10 +709,108 @@ EXPORT_SYMBOL(posix_acl_update_mode);
 /*
  * Fix up the uids and gids in posix acl extended attributes in place.
  */
+static int posix_acl_fix_xattr_common(void *value, size_t size)
+{
+	struct posix_acl_xattr_header *header = value;
+	int count;
+
+	if (!header)
+		return -EINVAL;
+	if (size < sizeof(struct posix_acl_xattr_header))
+		return -EINVAL;
+	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
+		return -EINVAL;
+
+	count = posix_acl_xattr_count(size);
+	if (count < 0)
+		return -EINVAL;
+	if (count == 0)
+		return -EINVAL;
+
+	return count;
+}
+
+void posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns,
+				     const struct inode *inode,
+				     void *value, size_t size)
+{
+	struct posix_acl_xattr_header *header = value;
+	struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
+	int count;
+	vfsuid_t vfsuid;
+	vfsgid_t vfsgid;
+	kuid_t uid;
+	kgid_t gid;
+
+	if (no_idmapping(mnt_userns, i_user_ns(inode)))
+		return;
+
+	count = posix_acl_fix_xattr_common(value, size);
+	if (count < 0)
+		return;
+
+	for (end = entry + count; entry != end; entry++) {
+		switch (le16_to_cpu(entry->e_tag)) {
+		case ACL_USER:
+			uid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id));
+			vfsuid = make_vfsuid(mnt_userns, &init_user_ns, uid);
+			entry->e_id = cpu_to_le32(from_kuid(&init_user_ns,
+						vfsuid_into_kuid(vfsuid)));
+			break;
+		case ACL_GROUP:
+			gid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id));
+			vfsgid = make_vfsgid(mnt_userns, &init_user_ns, gid);
+			entry->e_id = cpu_to_le32(from_kgid(&init_user_ns,
+						vfsgid_into_kgid(vfsgid)));
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+void posix_acl_setxattr_idmapped_mnt(struct user_namespace *mnt_userns,
+				     const struct inode *inode,
+				     void *value, size_t size)
+{
+	struct posix_acl_xattr_header *header = value;
+	struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
+	int count;
+	vfsuid_t vfsuid;
+	vfsgid_t vfsgid;
+	kuid_t uid;
+	kgid_t gid;
+
+	if (no_idmapping(mnt_userns, i_user_ns(inode)))
+		return;
+
+	count = posix_acl_fix_xattr_common(value, size);
+	if (count < 0)
+		return;
+
+	for (end = entry + count; entry != end; entry++) {
+		switch (le16_to_cpu(entry->e_tag)) {
+		case ACL_USER:
+			uid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id));
+			vfsuid = VFSUIDT_INIT(uid);
+			uid = from_vfsuid(mnt_userns, &init_user_ns, vfsuid);
+			entry->e_id = cpu_to_le32(from_kuid(&init_user_ns, uid));
+			break;
+		case ACL_GROUP:
+			gid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id));
+			vfsgid = VFSGIDT_INIT(gid);
+			gid = from_vfsgid(mnt_userns, &init_user_ns, vfsgid);
+			entry->e_id = cpu_to_le32(from_kgid(&init_user_ns, gid));
+			break;
+		default:
+			break;
+		}
+	}
+}
+
 static void posix_acl_fix_xattr_userns(
 	struct user_namespace *to, struct user_namespace *from,
-	struct user_namespace *mnt_userns,
-	void *value, size_t size, bool from_user)
+	void *value, size_t size)
 {
 	struct posix_acl_xattr_header *header = value;
 	struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
@@ -721,35 +818,18 @@ static void posix_acl_fix_xattr_userns(
 	kuid_t uid;
 	kgid_t gid;
 
-	if (!value)
-		return;
-	if (size < sizeof(struct posix_acl_xattr_header))
-		return;
-	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
-		return;
-
-	count = posix_acl_xattr_count(size);
+	count = posix_acl_fix_xattr_common(value, size);
 	if (count < 0)
 		return;
-	if (count == 0)
-		return;
 
 	for (end = entry + count; entry != end; entry++) {
 		switch(le16_to_cpu(entry->e_tag)) {
 		case ACL_USER:
 			uid = make_kuid(from, le32_to_cpu(entry->e_id));
-			if (from_user)
-				uid = mapped_kuid_user(mnt_userns, &init_user_ns, uid);
-			else
-				uid = mapped_kuid_fs(mnt_userns, &init_user_ns, uid);
 			entry->e_id = cpu_to_le32(from_kuid(to, uid));
 			break;
 		case ACL_GROUP:
 			gid = make_kgid(from, le32_to_cpu(entry->e_id));
-			if (from_user)
-				gid = mapped_kgid_user(mnt_userns, &init_user_ns, gid);
-			else
-				gid = mapped_kgid_fs(mnt_userns, &init_user_ns, gid);
 			entry->e_id = cpu_to_le32(from_kgid(to, gid));
 			break;
 		default:
@@ -758,34 +838,20 @@ static void posix_acl_fix_xattr_userns(
 	}
 }
 
-void posix_acl_fix_xattr_from_user(struct user_namespace *mnt_userns,
-				   struct inode *inode,
-				   void *value, size_t size)
+void posix_acl_fix_xattr_from_user(void *value, size_t size)
 {
 	struct user_namespace *user_ns = current_user_ns();
-
-	/* Leave ids untouched on non-idmapped mounts. */
-	if (no_idmapping(mnt_userns, i_user_ns(inode)))
-		mnt_userns = &init_user_ns;
-	if ((user_ns == &init_user_ns) && (mnt_userns == &init_user_ns))
+	if (user_ns == &init_user_ns)
 		return;
-	posix_acl_fix_xattr_userns(&init_user_ns, user_ns, mnt_userns, value,
-				   size, true);
+	posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
 }
 
-void posix_acl_fix_xattr_to_user(struct user_namespace *mnt_userns,
-				 struct inode *inode,
-				 void *value, size_t size)
+void posix_acl_fix_xattr_to_user(void *value, size_t size)
 {
 	struct user_namespace *user_ns = current_user_ns();
-
-	/* Leave ids untouched on non-idmapped mounts. */
-	if (no_idmapping(mnt_userns, i_user_ns(inode)))
-		mnt_userns = &init_user_ns;
-	if ((user_ns == &init_user_ns) && (mnt_userns == &init_user_ns))
+	if (user_ns == &init_user_ns)
 		return;
-	posix_acl_fix_xattr_userns(user_ns, &init_user_ns, mnt_userns, value,
-				   size, false);
+	posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
 }
 
 /*

fs/xattr.c

@@ -282,9 +282,15 @@ out:
 }
 EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
 
+static inline bool is_posix_acl_xattr(const char *name)
+{
+	return (strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
+	       (strcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0);
+}
+
 int
 vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
-	     const char *name, const void *value, size_t size, int flags)
+	     const char *name, void *value, size_t size, int flags)
 {
 	struct inode *inode = dentry->d_inode;
 	struct inode *delegated_inode = NULL;
@@ -292,12 +298,16 @@ vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 	int error;
 
 	if (size && strcmp(name, XATTR_NAME_CAPS) == 0) {
-		error = cap_convert_nscap(mnt_userns, dentry, &value, size);
+		error = cap_convert_nscap(mnt_userns, dentry,
+					  (const void **)&value, size);
 		if (error < 0)
 			return error;
 		size = error;
 	}
 
+	if (size && is_posix_acl_xattr(name))
+		posix_acl_setxattr_idmapped_mnt(mnt_userns, inode, value, size);
+
 retry_deleg:
 	inode_lock(inode);
 	error = __vfs_setxattr_locked(mnt_userns, dentry, name, value, size,
@@ -431,7 +441,10 @@ vfs_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		return ret;
 	}
 nolsm:
-	return __vfs_getxattr(dentry, inode, name, value, size);
+	error = __vfs_getxattr(dentry, inode, name, value, size);
+	if (error > 0 && is_posix_acl_xattr(name))
+		posix_acl_getxattr_idmapped_mnt(mnt_userns, inode, value, size);
+	return error;
 }
 EXPORT_SYMBOL_GPL(vfs_getxattr);
 
@@ -577,8 +590,7 @@ static void setxattr_convert(struct user_namespace *mnt_userns,
 	if (ctx->size &&
 		((strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
 		(strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)))
-		posix_acl_fix_xattr_from_user(mnt_userns, d_inode(d),
-						ctx->kvalue, ctx->size);
+		posix_acl_fix_xattr_from_user(ctx->kvalue, ctx->size);
 }
 
 int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
@@ -695,8 +707,7 @@ do_getxattr(struct user_namespace *mnt_userns, struct dentry *d,
 	if (error > 0) {
 		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
 		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
-			posix_acl_fix_xattr_to_user(mnt_userns, d_inode(d),
-							ctx->kvalue, error);
+			posix_acl_fix_xattr_to_user(ctx->kvalue, error);
 		if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error))
 			error = -EFAULT;
 	} else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) {

include/linux/mnt_idmapping.h

@@ -333,6 +333,19 @@ static inline bool vfsuid_has_fsmapping(struct user_namespace *mnt_userns,
 	return uid_valid(from_vfsuid(mnt_userns, fs_userns, vfsuid));
 }
 
+/**
+ * vfsuid_into_kuid - convert vfsuid into kuid
+ * @vfsuid: the vfsuid to convert
+ *
+ * This can be used when a vfsuid is committed as a kuid.
+ *
+ * Return: a kuid with the value of @vfsuid
+ */
+static inline kuid_t vfsuid_into_kuid(vfsuid_t vfsuid)
+{
+	return AS_KUIDT(vfsuid);
+}
+
 /**
  * from_vfsgid - map a vfsgid into the filesystem idmapping
  * @mnt_userns: the mount's idmapping
@@ -406,6 +419,19 @@ static inline bool vfsgid_has_fsmapping(struct user_namespace *mnt_userns,
 	return gid_valid(from_vfsgid(mnt_userns, fs_userns, vfsgid));
 }
 
+/**
+ * vfsgid_into_kgid - convert vfsgid into kgid
+ * @vfsgid: the vfsgid to convert
+ *
+ * This can be used when a vfsgid is committed as a kgid.
+ *
+ * Return: a kgid with the value of @vfsgid
+ */
+static inline kgid_t vfsgid_into_kgid(vfsgid_t vfsgid)
+{
+	return AS_KGIDT(vfsgid);
+}
+
 /**
  * mapped_fsuid - return caller's fsuid mapped up into a mnt_userns
  * @mnt_userns: the mount's idmapping

include/linux/posix_acl.h

@@ -73,6 +73,7 @@ extern int set_posix_acl(struct user_namespace *, struct inode *, int,
 			 struct posix_acl *);
 
 struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
+struct posix_acl *posix_acl_clone(const struct posix_acl *acl, gfp_t flags);
 
 #ifdef CONFIG_FS_POSIX_ACL
 int posix_acl_chmod(struct user_namespace *, struct inode *, umode_t);

include/linux/posix_acl_xattr.h

@@ -33,21 +33,31 @@ posix_acl_xattr_count(size_t size)
 }
 
 #ifdef CONFIG_FS_POSIX_ACL
-void posix_acl_fix_xattr_from_user(struct user_namespace *mnt_userns,
-				   struct inode *inode,
-				   void *value, size_t size);
-void posix_acl_fix_xattr_to_user(struct user_namespace *mnt_userns,
-				   struct inode *inode,
-				 void *value, size_t size);
+void posix_acl_fix_xattr_from_user(void *value, size_t size);
+void posix_acl_fix_xattr_to_user(void *value, size_t size);
+void posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns,
+				     const struct inode *inode,
+				     void *value, size_t size);
+void posix_acl_setxattr_idmapped_mnt(struct user_namespace *mnt_userns,
+				     const struct inode *inode,
+				     void *value, size_t size);
 #else
-static inline void posix_acl_fix_xattr_from_user(struct user_namespace *mnt_userns,
-						 struct inode *inode,
-						 void *value, size_t size)
+static inline void posix_acl_fix_xattr_from_user(void *value, size_t size)
 {
 }
-static inline void posix_acl_fix_xattr_to_user(struct user_namespace *mnt_userns,
-					       struct inode *inode,
-					       void *value, size_t size)
+static inline void posix_acl_fix_xattr_to_user(void *value, size_t size)
+{
+}
+static inline void
+posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns,
+				const struct inode *inode, void *value,
+				size_t size)
+{
+}
+static inline void
+posix_acl_setxattr_idmapped_mnt(struct user_namespace *mnt_userns,
+				const struct inode *inode, void *value,
+				size_t size)
 {
 }
 #endif

include/linux/xattr.h

@@ -61,7 +61,7 @@ int __vfs_setxattr_locked(struct user_namespace *, struct dentry *,
 			  const char *, const void *, size_t, int,
 			  struct inode **);
 int vfs_setxattr(struct user_namespace *, struct dentry *, const char *,
-		 const void *, size_t, int);
+		 void *, size_t, int);
 int __vfs_removexattr(struct user_namespace *, struct dentry *, const char *);
 int __vfs_removexattr_locked(struct user_namespace *, struct dentry *,
 			     const char *, struct inode **);