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From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Fri, 11 Jun 2010 16:12:52 +0530
Subject: [PATCH 16/16] ext4: Implement richacl support in ext4
Patch-mainline: not yet

Support the richacl permission model in ext4.  The richacls are stored
in "system.richacl" xattrs.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
---
 fs/ext4/Kconfig   |   10 +
 fs/ext4/Makefile  |    1 
 fs/ext4/ext4.h    |    4 
 fs/ext4/file.c    |    4 
 fs/ext4/ialloc.c  |    7 +
 fs/ext4/inode.c   |   19 ++-
 fs/ext4/namei.c   |    7 +
 fs/ext4/richacl.c |  293 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/richacl.h |   56 ++++++++++
 fs/ext4/super.c   |   45 +++++++-
 fs/ext4/xattr.c   |    6 +
 fs/ext4/xattr.h   |    5 
 12 files changed, 445 insertions(+), 12 deletions(-)
 create mode 100644 fs/ext4/richacl.c
 create mode 100644 fs/ext4/richacl.h

--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -83,3 +83,13 @@ config EXT4_DEBUG
 
 	  If you select Y here, then you will be able to turn on debugging
 	  with a command such as "echo 1 > /sys/kernel/debug/ext4/mballoc-debug"
+
+config EXT4_FS_RICHACL
+      bool "Ext4 Rich Access Control Lists (EXPERIMENTAL)"
+      depends on EXT4_FS_XATTR && EXPERIMENTAL
+      select FS_RICHACL
+      help
+	Rich ACLs are an implementation of NFSv4 ACLs, extended by file masks
+	to fit into the standard POSIX file permission model.  They are
+	designed to work seamlessly locally as well as across the NFSv4 and
+	CIFS/SMB2 network file system protocols.
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -12,3 +12,4 @@ ext4-y	:= balloc.o bitmap.o dir.o file.o
 ext4-$(CONFIG_EXT4_FS_XATTR)		+= xattr.o xattr_user.o xattr_trusted.o
 ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
 ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o
+ext4-$(CONFIG_EXT4_FS_RICHACL)		+= richacl.o
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -908,6 +908,10 @@ struct ext4_inode_info {
 	 */
 	tid_t i_sync_tid;
 	tid_t i_datasync_tid;
+#ifdef CONFIG_EXT4_FS_RICHACL
+	struct richacl   *i_richacl;
+#endif
+
 };
 
 /*
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -28,6 +28,7 @@
 #include "ext4_jbd2.h"
 #include "xattr.h"
 #include "acl.h"
+#include "richacl.h"
 
 /*
  * Called when an inode is released. Note that this is different
@@ -258,5 +259,8 @@ const struct inode_operations ext4_file_
 #endif
 	.get_acl	= ext4_get_acl,
 	.fiemap		= ext4_fiemap,
+	.permission	= ext4_permission,
+	.may_create	= ext4_may_create,
+	.may_delete	= ext4_may_delete,
 };
 
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -28,6 +28,7 @@
 #include "ext4_jbd2.h"
 #include "xattr.h"
 #include "acl.h"
+#include "richacl.h"
 
 #include <trace/events/ext4.h>
 
@@ -861,7 +862,11 @@ got:
 	if (err)
 		goto fail_drop;
 
-	err = ext4_init_acl(handle, inode, dir);
+	if (EXT4_IS_RICHACL(dir))
+		err = ext4_init_richacl(handle, inode, dir);
+	else
+		err = ext4_init_acl(handle, inode, dir);
+
 	if (err)
 		goto fail_free_drop;
 
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -42,6 +42,7 @@
 #include "xattr.h"
 #include "acl.h"
 #include "truncate.h"
+#include "richacl.h"
 
 #include <trace/events/ext4.h>
 
@@ -3654,6 +3655,9 @@ struct inode *ext4_iget(struct super_blo
 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
 
 	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
+#ifdef CONFIG_EXT4_FS_RICHACL
+	ei->i_richacl = EXT4_RICHACL_NOT_CACHED;
+#endif
 	ei->i_dir_start_lookup = 0;
 	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
 	/* We now have enough fields to check if the inode was active or not.
@@ -4078,7 +4082,11 @@ int ext4_setattr(struct dentry *dentry,
 	int orphan = 0;
 	const unsigned int ia_valid = attr->ia_valid;
 
-	error = inode_change_ok(inode, attr);
+	if (EXT4_IS_RICHACL(inode))
+		error = richacl_inode_change_ok(inode, attr,
+						ext4_richacl_permission);
+	else
+		error = inode_change_ok(inode, attr);
 	if (error)
 		return error;
 
@@ -4178,9 +4186,12 @@ int ext4_setattr(struct dentry *dentry,
 	if (orphan && inode->i_nlink)
 		ext4_orphan_del(NULL, inode);
 
-	if (!rc && (ia_valid & ATTR_MODE))
-		rc = ext4_acl_chmod(inode);
-
+	if (!rc && (ia_valid & ATTR_MODE)) {
+		if (EXT4_IS_RICHACL(inode))
+			rc = ext4_richacl_chmod(inode);
+		else
+			rc = ext4_acl_chmod(inode);
+	}
 err_out:
 	ext4_std_error(inode->i_sb, error);
 	if (!error)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -39,6 +39,7 @@
 
 #include "xattr.h"
 #include "acl.h"
+#include "richacl.h"
 
 #include <trace/events/ext4.h>
 /*
@@ -2587,6 +2588,9 @@ const struct inode_operations ext4_dir_i
 #endif
 	.get_acl	= ext4_get_acl,
 	.fiemap         = ext4_fiemap,
+	.permission	= ext4_permission,
+	.may_create	= ext4_may_create,
+	.may_delete	= ext4_may_delete,
 };
 
 const struct inode_operations ext4_special_inode_operations = {
@@ -2598,4 +2602,7 @@ const struct inode_operations ext4_speci
 	.removexattr	= generic_removexattr,
 #endif
 	.get_acl	= ext4_get_acl,
+	.permission	= ext4_permission,
+	.may_create	= ext4_may_create,
+	.may_delete	= ext4_may_delete,
 };
--- /dev/null
+++ b/fs/ext4/richacl.c
@@ -0,0 +1,293 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/richacl_xattr.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "richacl.h"
+
+static inline struct richacl *
+ext4_iget_richacl(struct inode *inode)
+{
+	struct richacl *acl = EXT4_RICHACL_NOT_CACHED;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	spin_lock(&inode->i_lock);
+	if (ei->i_richacl != EXT4_RICHACL_NOT_CACHED)
+		acl = richacl_get(ei->i_richacl);
+	spin_unlock(&inode->i_lock);
+
+	return acl;
+}
+
+static inline void
+ext4_iset_richacl(struct inode *inode, struct richacl *acl)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	spin_lock(&inode->i_lock);
+	if (ei->i_richacl != EXT4_RICHACL_NOT_CACHED)
+		richacl_put(ei->i_richacl);
+	ei->i_richacl = richacl_get(acl);
+	spin_unlock(&inode->i_lock);
+}
+
+static struct richacl *
+ext4_get_richacl(struct inode *inode)
+{
+	const int name_index = EXT4_XATTR_INDEX_RICHACL;
+	void *value = NULL;
+	struct richacl *acl;
+	int retval;
+
+	if (!IS_RICHACL(inode))
+		return ERR_PTR(-EOPNOTSUPP);
+	acl = ext4_iget_richacl(inode);
+	if (acl != EXT4_RICHACL_NOT_CACHED)
+		return acl;
+	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
+	if (retval > 0) {
+		value = kmalloc(retval, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		retval = ext4_xattr_get(inode, name_index, "", value, retval);
+	}
+	if (retval > 0) {
+		acl = richacl_from_xattr(value, retval);
+		if (acl == ERR_PTR(-EINVAL))
+			acl = ERR_PTR(-EIO);
+	} else if (retval == -ENODATA || retval == -ENOSYS)
+		acl = NULL;
+	else
+		acl = ERR_PTR(retval);
+	kfree(value);
+
+	if (!IS_ERR_OR_NULL(acl))
+		ext4_iset_richacl(inode, acl);
+
+	return acl;
+}
+
+static int
+ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
+{
+	const int name_index = EXT4_XATTR_INDEX_RICHACL;
+	size_t size = 0;
+	void *value = NULL;
+	int retval;
+
+	if (acl) {
+		mode_t mode = inode->i_mode;
+		if (richacl_equiv_mode(acl, &mode) == 0) {
+			inode->i_mode = mode;
+			ext4_mark_inode_dirty(handle, inode);
+			acl = NULL;
+		}
+	}
+	if (acl) {
+		size = richacl_xattr_size(acl);
+		value = kmalloc(size, GFP_KERNEL);
+		if (!value)
+			return -ENOMEM;
+		richacl_to_xattr(acl, value);
+	}
+	if (handle)
+		retval = ext4_xattr_set_handle(handle, inode, name_index, "",
+					       value, size, 0);
+	else
+		retval = ext4_xattr_set(inode, name_index, "", value, size, 0);
+	kfree(value);
+	if (!retval)
+		ext4_iset_richacl(inode, acl);
+
+	return retval;
+}
+
+int
+ext4_richacl_permission(struct inode *inode, unsigned int mask)
+{
+	struct richacl *acl;
+	int retval;
+
+	if (!IS_RICHACL(inode))
+		BUG();
+
+	acl = ext4_get_richacl(inode);
+	if (acl && IS_ERR(acl))
+		retval = PTR_ERR(acl);
+	else {
+		retval = richacl_inode_permission(inode, acl, mask);
+		richacl_put(acl);
+	}
+
+	return retval;
+}
+
+int ext4_permission(struct inode *inode, int mask)
+{
+	if (IS_RICHACL(inode))
+		return ext4_richacl_permission(inode,
+					richacl_want_to_mask(mask));
+	else
+		return generic_permission(inode, mask);
+}
+
+int ext4_may_create(struct inode *dir, int isdir)
+{
+	return richacl_may_create(dir, isdir, ext4_richacl_permission);
+}
+
+int ext4_may_delete(struct inode *dir, struct inode *inode, int replace)
+{
+	return richacl_may_delete(dir, inode, replace, ext4_richacl_permission);
+}
+
+int
+ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	struct richacl *dir_acl = NULL;
+
+	if (!S_ISLNK(inode->i_mode)) {
+		dir_acl = ext4_get_richacl(dir);
+		if (IS_ERR(dir_acl))
+			return PTR_ERR(dir_acl);
+	}
+	if (dir_acl) {
+		struct richacl *acl;
+		int retval;
+
+		acl = richacl_inherit(dir_acl, inode);
+		richacl_put(dir_acl);
+
+		retval = PTR_ERR(acl);
+		if (acl && !IS_ERR(acl)) {
+			retval = ext4_set_richacl(handle, inode, acl);
+			richacl_put(acl);
+		}
+		return retval;
+	} else {
+		inode->i_mode &= ~current_umask();
+		return 0;
+	}
+}
+
+int
+ext4_richacl_chmod(struct inode *inode)
+{
+	struct richacl *acl;
+	int retval;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	acl = ext4_get_richacl(inode);
+	if (IS_ERR_OR_NULL(acl))
+		return PTR_ERR(acl);
+	acl = richacl_chmod(acl, inode->i_mode);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	retval = ext4_set_richacl(NULL, inode, acl);
+	richacl_put(acl);
+
+	return retval;
+}
+
+static size_t
+ext4_xattr_list_richacl(struct dentry *dentry, char *list, size_t list_len,
+			const char *name, size_t name_len, int type)
+{
+	const size_t size = sizeof(RICHACL_XATTR);
+	if (!IS_RICHACL(dentry->d_inode))
+		return 0;
+	if (list && size <= list_len)
+		memcpy(list, RICHACL_XATTR, size);
+	return size;
+}
+
+static int
+ext4_xattr_get_richacl(struct dentry *dentry, const char *name, void *buffer,
+		size_t buffer_size, int type)
+{
+	struct richacl *acl;
+	size_t size;
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	acl = ext4_get_richacl(dentry->d_inode);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl == NULL)
+		return -ENODATA;
+	size = richacl_xattr_size(acl);
+	if (buffer) {
+		if (size > buffer_size)
+			return -ERANGE;
+		richacl_to_xattr(acl, buffer);
+	}
+	richacl_put(acl);
+
+	return size;
+}
+
+static int
+ext4_xattr_set_richacl(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	handle_t *handle;
+	struct richacl *acl = NULL;
+	int retval, retries = 0;
+	struct inode *inode = dentry->d_inode;
+
+	if (!IS_RICHACL(dentry->d_inode))
+		return -EOPNOTSUPP;
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	if (current_fsuid() != inode->i_uid &&
+	    ext4_richacl_permission(inode, ACE4_WRITE_ACL) &&
+	    !capable(CAP_FOWNER))
+		return -EPERM;
+	if (value) {
+		acl = richacl_from_xattr(value, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+
+		inode->i_mode &= ~S_IRWXUGO;
+		inode->i_mode |= richacl_masks_to_mode(acl);
+	}
+
+retry:
+	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ext4_mark_inode_dirty(handle, inode);
+	retval = ext4_set_richacl(handle, inode, acl);
+	ext4_journal_stop(handle);
+	if (retval == ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+	richacl_put(acl);
+	return retval;
+}
+
+const struct xattr_handler ext4_richacl_xattr_handler = {
+	.prefix	= RICHACL_XATTR,
+	.list	= ext4_xattr_list_richacl,
+	.get	= ext4_xattr_get_richacl,
+	.set	= ext4_xattr_set_richacl,
+};
--- /dev/null
+++ b/fs/ext4/richacl.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#ifndef __FS_EXT4_RICHACL_H
+#define __FS_EXT4_RICHACL_H
+
+#include <linux/richacl.h>
+
+#ifdef CONFIG_EXT4_FS_RICHACL
+
+# define EXT4_IS_RICHACL(inode) IS_RICHACL(inode)
+
+/* Value for i_richacl if RICHACL has not been cached */
+# define EXT4_RICHACL_NOT_CACHED ((void *)-1)
+
+extern int ext4_permission(struct inode *, int);
+extern int ext4_richacl_permission(struct inode *, unsigned int);
+extern int ext4_may_create(struct inode *, int);
+extern int ext4_may_delete(struct inode *, struct inode *, int);
+extern int ext4_init_richacl(handle_t *, struct inode *, struct inode *);
+extern int ext4_richacl_chmod(struct inode *);
+
+#else  /* CONFIG_FS_EXT4_RICHACL */
+
+# define EXT4_IS_RICHACL(inode) (0)
+
+# define ext4_permission NULL
+# define ext4_may_create NULL
+# define ext4_may_delete NULL
+# define ext4_richacl_permission NULL
+
+static inline int
+ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	return 0;
+}
+
+static inline int
+ext4_richacl_chmod(struct inode *inode)
+{
+	return 0;
+}
+
+#endif  /* CONFIG_FS_EXT4_RICHACL */
+#endif  /* __FS_EXT4_RICHACL_H */
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -50,6 +50,7 @@
 #include "xattr.h"
 #include "acl.h"
 #include "mballoc.h"
+#include "richacl.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/ext4.h>
@@ -921,7 +922,9 @@ static struct inode *ext4_alloc_inode(st
 	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
 	if (!ei)
 		return NULL;
-
+#ifdef CONFIG_EXT4_FS_RICHACL
+	ei->i_richacl = EXT4_RICHACL_NOT_CACHED;
+#endif
 	ei->vfs_inode.i_version = 1;
 	ei->vfs_inode.i_data.writeback_index = 0;
 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
@@ -1009,6 +1012,13 @@ void ext4_clear_inode(struct inode *inod
 	invalidate_inode_buffers(inode);
 	end_writeback(inode);
 	dquot_drop(inode);
+#ifdef CONFIG_EXT4_FS_RICHACL
+	if (EXT4_I(inode)->i_richacl &&
+		EXT4_I(inode)->i_richacl != EXT4_RICHACL_NOT_CACHED) {
+		richacl_put(EXT4_I(inode)->i_richacl);
+		EXT4_I(inode)->i_richacl = EXT4_RICHACL_NOT_CACHED;
+	}
+#endif
 	ext4_discard_preallocations(inode);
 	if (EXT4_I(inode)->jinode) {
 		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
@@ -1171,7 +1181,7 @@ enum {
 	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
 	Opt_nouid32, Opt_debug, Opt_removed,
-	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
+	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_richacl, Opt_noacl,
 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
 	Opt_journal_dev, Opt_journal_checksum, Opt_journal_async_commit,
@@ -1208,6 +1218,7 @@ static const match_table_t tokens = {
 	{Opt_user_xattr, "user_xattr"},
 	{Opt_nouser_xattr, "nouser_xattr"},
 	{Opt_acl, "acl"},
+	{Opt_richacl, "richacl"},
 	{Opt_noacl, "noacl"},
 	{Opt_noload, "norecovery"},
 	{Opt_noload, "noload"},
@@ -1457,6 +1468,9 @@ static int handle_mount_opt(struct super
 	case Opt_nouser_xattr:
 		ext4_msg(sb, KERN_WARNING, deprecated_msg, opt, "3.5");
 		break;
+	case Opt_richacl:
+		sb->s_flags |= MS_RICHACL;
+		return 1;
 	case Opt_sb:
 		return 1;	/* handled by get_sb_block() */
 	case Opt_removed:
@@ -1648,6 +1662,10 @@ static int parse_options(char *options,
 		}
 	}
 #endif
+#if defined(CONFIG_EXT4_FS_RICHACL) && defined(CONFIG_EXT4_FS_POSIX_ACL)
+	if (test_opt(sb, POSIX_ACL) && (sb->s_flags & MS_RICHACL))
+		clear_opt(sb, POSIX_ACL);
+#endif
 	return 1;
 }
 
@@ -1772,6 +1790,9 @@ static int _ext4_show_options(struct seq
 		       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
 		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
 
+	if (sb->s_flags & MS_RICHACL)
+		SEQ_OPTS_PUTS("richacl");
+
 	ext4_show_quota_options(seq, sb);
 	return 0;
 }
@@ -2983,6 +3004,7 @@ static int ext4_fill_super(struct super_
 	int err;
 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
 	ext4_group_t first_not_zeroed;
+	unsigned long acl_flags = 0;
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
@@ -3054,7 +3076,7 @@ static int ext4_fill_super(struct super_
 #ifdef CONFIG_EXT4_FS_XATTR
 	set_opt(sb, XATTR_USER);
 #endif
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
+#if defined(CONFIG_EXT4_FS_POSIX_ACL)
 	set_opt(sb, POSIX_ACL);
 #endif
 	set_opt(sb, MBLK_IO_SUBMIT);
@@ -3137,8 +3159,12 @@ static int ext4_fill_super(struct super_
 		}
 	}
 
-	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
-		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
+	if (sb->s_flags & MS_RICHACL)
+		acl_flags = MS_RICHACL;
+	else if (test_opt(sb, POSIX_ACL))
+		acl_flags = MS_POSIXACL;
+
+	sb->s_flags = (sb->s_flags & ~(MS_POSIXACL | MS_RICHACL)) | acl_flags;
 
 	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
 	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
@@ -4249,6 +4275,7 @@ static int ext4_remount(struct super_blo
 	ext4_group_t g;
 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
 	int err = 0;
+	unsigned long acl_flags = 0;
 #ifdef CONFIG_QUOTA
 	int i;
 #endif
@@ -4283,8 +4310,12 @@ static int ext4_remount(struct super_blo
 	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
 		ext4_abort(sb, "Abort forced by user");
 
-	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
-		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
+	if (sb->s_flags & MS_RICHACL)
+		acl_flags = MS_RICHACL;
+	else if (test_opt(sb, POSIX_ACL))
+		acl_flags = MS_POSIXACL;
+
+	sb->s_flags = (sb->s_flags & ~(MS_POSIXACL | MS_RICHACL)) | acl_flags;
 
 	es = sbi->s_es;
 
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -107,6 +107,9 @@ static const struct xattr_handler *ext4_
 #ifdef CONFIG_EXT4_FS_SECURITY
 	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
 #endif
+#ifdef CONFIG_EXT4_FS_RICHACL
+	[EXT4_XATTR_INDEX_RICHACL]           = &ext4_richacl_xattr_handler,
+#endif
 };
 
 const struct xattr_handler *ext4_xattr_handlers[] = {
@@ -119,6 +122,9 @@ const struct xattr_handler *ext4_xattr_h
 #ifdef CONFIG_EXT4_FS_SECURITY
 	&ext4_xattr_security_handler,
 #endif
+#ifdef CONFIG_EXT4_FS_RICHACL
+	&ext4_richacl_xattr_handler,
+#endif
 	NULL
 };
 
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -21,6 +21,7 @@
 #define EXT4_XATTR_INDEX_TRUSTED		4
 #define	EXT4_XATTR_INDEX_LUSTRE			5
 #define EXT4_XATTR_INDEX_SECURITY	        6
+#define EXT4_XATTR_INDEX_RICHACL		7
 
 struct ext4_xattr_header {
 	__le32	h_magic;	/* magic number for identification */
@@ -70,6 +71,10 @@ extern const struct xattr_handler ext4_x
 extern const struct xattr_handler ext4_xattr_acl_access_handler;
 extern const struct xattr_handler ext4_xattr_acl_default_handler;
 extern const struct xattr_handler ext4_xattr_security_handler;
+extern const struct xattr_handler ext4_xattr_acl_access_handler;
+extern const struct xattr_handler ext4_xattr_acl_default_handler;
+extern const struct xattr_handler ext4_xattr_security_handler;
+extern const struct xattr_handler ext4_richacl_xattr_handler;
 
 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);