[PATCH 0/2] Support for posix ACLs in fuse

@@ -5,4 +5,4 @@
 obj-$(CONFIG_FUSE_FS) += fuse.o
 obj-$(CONFIG_CUSE) += cuse.o
 
-fuse-objs := dev.o dir.o file.o inode.o control.o
+fuse-objs := dev.o dir.o file.o inode.o control.o xattr.o

@@ -13,6 +13,7 @@
 #include <linux/sched.h>
 #include <linux/namei.h>
 #include <linux/slab.h>
+#include <linux/xattr.h>
 
 static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx)
 {

@@ -634,7 +635,7 @@ static int fuse_symlink(struct inode *dir, struct dentry *entry,
 	return create_new_entry(fc, &args, dir, entry, S_IFLNK);
 }
 
-static inline void fuse_update_ctime(struct inode *inode)
+void fuse_update_ctime(struct inode *inode)
 {
 	if (!IS_NOCMTIME(inode)) {
 		inode->i_ctime = current_fs_time(inode->i_sb);

@@ -1724,152 +1725,6 @@ static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
 	return fuse_update_attributes(inode, stat, NULL, NULL);
 }
 
-static int fuse_setxattr(struct dentry *unused, struct inode *inode,
-			 const char *name, const void *value,
-			 size_t size, int flags)
-{
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	FUSE_ARGS(args);
-	struct fuse_setxattr_in inarg;
-	int err;
-
-	if (fc->no_setxattr)
-		return -EOPNOTSUPP;
-
-	memset(&inarg, 0, sizeof(inarg));
-	inarg.size = size;
-	inarg.flags = flags;
-	args.in.h.opcode = FUSE_SETXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 3;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = strlen(name) + 1;
-	args.in.args[1].value = name;
-	args.in.args[2].size = size;
-	args.in.args[2].value = value;
-	err = fuse_simple_request(fc, &args);
-	if (err == -ENOSYS) {
-		fc->no_setxattr = 1;
-		err = -EOPNOTSUPP;
-	}
-	if (!err) {
-		fuse_invalidate_attr(inode);
-		fuse_update_ctime(inode);
-	}
-	return err;
-}
-
-static ssize_t fuse_getxattr(struct dentry *entry, struct inode *inode,
-			     const char *name, void *value, size_t size)
-{
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	FUSE_ARGS(args);
-	struct fuse_getxattr_in inarg;
-	struct fuse_getxattr_out outarg;
-	ssize_t ret;
-
-	if (fc->no_getxattr)
-		return -EOPNOTSUPP;
-
-	memset(&inarg, 0, sizeof(inarg));
-	inarg.size = size;
-	args.in.h.opcode = FUSE_GETXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 2;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	args.in.args[1].size = strlen(name) + 1;
-	args.in.args[1].value = name;
-	/* This is really two different operations rolled into one */
-	args.out.numargs = 1;
-	if (size) {
-		args.out.argvar = 1;
-		args.out.args[0].size = size;
-		args.out.args[0].value = value;
-	} else {
-		args.out.args[0].size = sizeof(outarg);
-		args.out.args[0].value = &outarg;
-	}
-	ret = fuse_simple_request(fc, &args);
-	if (!ret && !size)
-		ret = outarg.size;
-	if (ret == -ENOSYS) {
-		fc->no_getxattr = 1;
-		ret = -EOPNOTSUPP;
-	}
-	return ret;
-}
-
-static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
-{
-	struct inode *inode = d_inode(entry);
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	FUSE_ARGS(args);
-	struct fuse_getxattr_in inarg;
-	struct fuse_getxattr_out outarg;
-	ssize_t ret;
-
-	if (!fuse_allow_current_process(fc))
-		return -EACCES;
-
-	if (fc->no_listxattr)
-		return -EOPNOTSUPP;
-
-	memset(&inarg, 0, sizeof(inarg));
-	inarg.size = size;
-	args.in.h.opcode = FUSE_LISTXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = sizeof(inarg);
-	args.in.args[0].value = &inarg;
-	/* This is really two different operations rolled into one */
-	args.out.numargs = 1;
-	if (size) {
-		args.out.argvar = 1;
-		args.out.args[0].size = size;
-		args.out.args[0].value = list;
-	} else {
-		args.out.args[0].size = sizeof(outarg);
-		args.out.args[0].value = &outarg;
-	}
-	ret = fuse_simple_request(fc, &args);
-	if (!ret && !size)
-		ret = outarg.size;
-	if (ret == -ENOSYS) {
-		fc->no_listxattr = 1;
-		ret = -EOPNOTSUPP;
-	}
-	return ret;
-}
-
-static int fuse_removexattr(struct dentry *entry, const char *name)
-{
-	struct inode *inode = d_inode(entry);
-	struct fuse_conn *fc = get_fuse_conn(inode);
-	FUSE_ARGS(args);
-	int err;
-
-	if (fc->no_removexattr)
-		return -EOPNOTSUPP;
-
-	args.in.h.opcode = FUSE_REMOVEXATTR;
-	args.in.h.nodeid = get_node_id(inode);
-	args.in.numargs = 1;
-	args.in.args[0].size = strlen(name) + 1;
-	args.in.args[0].value = name;
-	err = fuse_simple_request(fc, &args);
-	if (err == -ENOSYS) {
-		fc->no_removexattr = 1;
-		err = -EOPNOTSUPP;
-	}
-	if (!err) {
-		fuse_invalidate_attr(inode);
-		fuse_update_ctime(inode);
-	}
-	return err;
-}
-
 static const struct inode_operations fuse_dir_inode_operations = {
 	.lookup		= fuse_lookup,
 	.mkdir		= fuse_mkdir,

@@ -1884,10 +1739,10 @@ static const struct inode_operations fuse_dir_inode_operations = {
 	.mknod		= fuse_mknod,
 	.permission	= fuse_permission,
 	.getattr	= fuse_getattr,
-	.setxattr	= fuse_setxattr,
-	.getxattr	= fuse_getxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= fuse_listxattr,
-	.removexattr	= fuse_removexattr,
+	.removexattr	= generic_removexattr,
 };
 
 static const struct file_operations fuse_dir_operations = {

@@ -1905,10 +1760,10 @@ static const struct inode_operations fuse_common_inode_operations = {
 	.setattr	= fuse_setattr,
 	.permission	= fuse_permission,
 	.getattr	= fuse_getattr,
-	.setxattr	= fuse_setxattr,
-	.getxattr	= fuse_getxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= fuse_listxattr,
-	.removexattr	= fuse_removexattr,
+	.removexattr	= generic_removexattr,
 };
 
 static const struct inode_operations fuse_symlink_inode_operations = {

@@ -1916,10 +1771,10 @@ static const struct inode_operations fuse_symlink_inode_operations = {
 	.get_link	= fuse_get_link,
 	.readlink	= generic_readlink,
 	.getattr	= fuse_getattr,
-	.setxattr	= fuse_setxattr,
-	.getxattr	= fuse_getxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= fuse_listxattr,
-	.removexattr	= fuse_removexattr,
+	.removexattr	= generic_removexattr,
 };
 
 void fuse_init_common(struct inode *inode)

@@ -902,6 +902,8 @@ int fuse_allow_current_process(struct fuse_conn *fc);
 
 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 
+void fuse_update_ctime(struct inode *inode);
+
 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 			   struct file *file, bool *refreshed);
 

@@ -966,4 +968,7 @@ void fuse_set_initialized(struct fuse_conn *fc);
 void fuse_unlock_inode(struct inode *inode);
 void fuse_lock_inode(struct inode *inode);
 
+ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
+extern const struct xattr_handler *fuse_xattr_handlers[];
+
 #endif /* _FS_FUSE_I_H */

@@ -1071,6 +1071,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	}
 	sb->s_magic = FUSE_SUPER_MAGIC;
 	sb->s_op = &fuse_super_operations;
+	sb->s_xattr = fuse_xattr_handlers;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_time_gran = 1;
 	sb->s_export_op = &fuse_export_operations;

@@ -0,0 +1,184 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
+
+  This program can be distributed under the terms of the GNU GPL.
+  See the file COPYING.
+*/
+
+#include "fuse_i.h"
+
+#include <linux/xattr.h>
+
+static int fuse_setxattr(struct inode *inode, const char *name,
+			 const void *value, size_t size, int flags)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	FUSE_ARGS(args);
+	struct fuse_setxattr_in inarg;
+	int err;
+
+	if (fc->no_setxattr)
+		return -EOPNOTSUPP;
+
+	memset(&inarg, 0, sizeof(inarg));
+	inarg.size = size;
+	inarg.flags = flags;
+	args.in.h.opcode = FUSE_SETXATTR;
+	args.in.h.nodeid = get_node_id(inode);
+	args.in.numargs = 3;
+	args.in.args[0].size = sizeof(inarg);
+	args.in.args[0].value = &inarg;
+	args.in.args[1].size = strlen(name) + 1;
+	args.in.args[1].value = name;
+	args.in.args[2].size = size;
+	args.in.args[2].value = value;
+	err = fuse_simple_request(fc, &args);
+	if (err == -ENOSYS) {
+		fc->no_setxattr = 1;
+		err = -EOPNOTSUPP;
+	}
+	if (!err) {
+		fuse_invalidate_attr(inode);
+		fuse_update_ctime(inode);
+	}
+	return err;
+}
+
+static ssize_t fuse_getxattr(struct inode *inode, const char *name,
+			     void *value, size_t size)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	FUSE_ARGS(args);
+	struct fuse_getxattr_in inarg;
+	struct fuse_getxattr_out outarg;
+	ssize_t ret;
+
+	if (fc->no_getxattr)
+		return -EOPNOTSUPP;
+
+	memset(&inarg, 0, sizeof(inarg));
+	inarg.size = size;
+	args.in.h.opcode = FUSE_GETXATTR;
+	args.in.h.nodeid = get_node_id(inode);
+	args.in.numargs = 2;
+	args.in.args[0].size = sizeof(inarg);
+	args.in.args[0].value = &inarg;
+	args.in.args[1].size = strlen(name) + 1;
+	args.in.args[1].value = name;
+	/* This is really two different operations rolled into one */
+	args.out.numargs = 1;
+	if (size) {
+		args.out.argvar = 1;
+		args.out.args[0].size = size;
+		args.out.args[0].value = value;
+	} else {
+		args.out.args[0].size = sizeof(outarg);
+		args.out.args[0].value = &outarg;
+	}
+	ret = fuse_simple_request(fc, &args);
+	if (!ret && !size)
+		ret = outarg.size;
+	if (ret == -ENOSYS) {
+		fc->no_getxattr = 1;
+		ret = -EOPNOTSUPP;
+	}
+	return ret;
+}
+
+ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
+{
+	struct inode *inode = d_inode(entry);
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	FUSE_ARGS(args);
+	struct fuse_getxattr_in inarg;
+	struct fuse_getxattr_out outarg;
+	ssize_t ret;
+
+	if (!fuse_allow_current_process(fc))
+		return -EACCES;
+
+	if (fc->no_listxattr)
+		return -EOPNOTSUPP;
+
+	memset(&inarg, 0, sizeof(inarg));
+	inarg.size = size;
+	args.in.h.opcode = FUSE_LISTXATTR;
+	args.in.h.nodeid = get_node_id(inode);
+	args.in.numargs = 1;
+	args.in.args[0].size = sizeof(inarg);
+	args.in.args[0].value = &inarg;
+	/* This is really two different operations rolled into one */
+	args.out.numargs = 1;
+	if (size) {
+		args.out.argvar = 1;
+		args.out.args[0].size = size;
+		args.out.args[0].value = list;
+	} else {
+		args.out.args[0].size = sizeof(outarg);
+		args.out.args[0].value = &outarg;
+	}
+	ret = fuse_simple_request(fc, &args);
+	if (!ret && !size)
+		ret = outarg.size;
+	if (ret == -ENOSYS) {
+		fc->no_listxattr = 1;
+		ret = -EOPNOTSUPP;
+	}
+	return ret;
+}
+
+static int fuse_removexattr(struct inode *inode, const char *name)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	FUSE_ARGS(args);
+	int err;
+
+	if (fc->no_removexattr)
+		return -EOPNOTSUPP;
+
+	args.in.h.opcode = FUSE_REMOVEXATTR;
+	args.in.h.nodeid = get_node_id(inode);
+	args.in.numargs = 1;
+	args.in.args[0].size = strlen(name) + 1;
+	args.in.args[0].value = name;
+	err = fuse_simple_request(fc, &args);
+	if (err == -ENOSYS) {
+		fc->no_removexattr = 1;
+		err = -EOPNOTSUPP;
+	}
+	if (!err) {
+		fuse_invalidate_attr(inode);
+		fuse_update_ctime(inode);
+	}
+	return err;
+}
+
+static int fuse_xattr_get(const struct xattr_handler *handler,
+			 struct dentry *dentry, struct inode *inode,
+			 const char *name, void *value, size_t size)
+{
+	return fuse_getxattr(inode, name, value, size);
+}
+
+static int fuse_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 fuse_removexattr(inode, name);
+
+	return fuse_setxattr(inode, name, value, size, flags);
+}
+
+static const struct xattr_handler fuse_xattr_handler = {
+	.prefix = "",
+	.get    = fuse_xattr_get,
+	.set    = fuse_xattr_set,
+};
+
+const struct xattr_handler *fuse_xattr_handlers[] = {
+	&fuse_xattr_handler,
+	NULL
+};

@@ -1,5 +1,6 @@
 config FUSE_FS
 	tristate "FUSE (Filesystem in Userspace) support"
+	select FS_POSIX_ACL
 	help
 	  With FUSE it is possible to implement a fully functional filesystem
 	  in a userspace program.

@@ -5,4 +5,4 @@
 obj-$(CONFIG_FUSE_FS) += fuse.o
 obj-$(CONFIG_CUSE) += cuse.o
 
-fuse-objs := dev.o dir.o file.o inode.o control.o xattr.o
+fuse-objs := dev.o dir.o file.o inode.o control.o xattr.o acl.o

@@ -0,0 +1,100 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2016 Canonical Ltd. <seth.forshee@canonical.com>
+
+  This program can be distributed under the terms of the GNU GPL.
+  See the file COPYING.
+*/
+
+#include "fuse_i.h"
+
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
+
+struct posix_acl *fuse_get_acl(struct inode *inode, int type)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	int size;
+	const char *name;
+	void *value = NULL;
+	struct posix_acl *acl;
+
+	if (!fc->posix_acl || fc->no_getxattr)
+		return NULL;
+
+	if (type == ACL_TYPE_ACCESS)
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
+	else if (type == ACL_TYPE_DEFAULT)
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
+	else
+		return ERR_PTR(-EOPNOTSUPP);
+
+	value = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!value)
+		return ERR_PTR(-ENOMEM);
+	size = fuse_getxattr(inode, name, value, PAGE_SIZE);
+	if (size == -ERANGE) {
+		kfree(value);
+		size = fuse_getxattr(inode, name, NULL, 0);
+		value = kmalloc(size, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		size = fuse_getxattr(inode, name, value, size);
+	}
+
+	if (size > 0)
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
+	else if ((size == 0) || (size == -ENODATA) ||
+		 (size == -EOPNOTSUPP && fc->no_getxattr))
+		acl = NULL;
+	else
+		acl = ERR_PTR(size);
+
+	kfree(value);
+	return acl;
+}
+
+int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	const char *name;
+	int ret;
+
+	if (!fc->posix_acl || fc->no_setxattr)
+		return -EOPNOTSUPP;
+
+	if (type == ACL_TYPE_ACCESS)
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
+	else if (type == ACL_TYPE_DEFAULT)
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
+	else
+		return -EINVAL;
+
+	if (acl) {
+		/*
+		 * Fuse userspace is responsible for updating access
+		 * permissions in the inode, if needed. fuse_setxattr
+		 * invalidates the inode attributes, which will force
+		 * them to be refreshed the next time they are used,
+		 * and it also updates i_ctime.
+		 */
+		size_t size = posix_acl_xattr_size(acl->a_count);
+		void *value = kmalloc(size, GFP_KERNEL);
+		if (!value)
+			return -ENOMEM;
+
+		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+		if (ret < 0) {
+			kfree(value);
+			return ret;
+		}
+
+		ret = fuse_setxattr(inode, name, value, size, 0);
+		kfree(value);
+	} else {
+		ret = fuse_removexattr(inode, name);
+	}
+	if (ret == 0)
+		set_cached_acl(inode, type, acl);
+	return ret;
+}

@@ -14,6 +14,7 @@
 #include <linux/namei.h>
 #include <linux/slab.h>
 #include <linux/xattr.h>
+#include <linux/posix_acl.h>
 
 static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx)
 {

@@ -244,6 +245,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 		if (ret || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
 			goto invalid;
 
+		forget_all_cached_acls(inode);
 		fuse_change_attributes(inode, &outarg.attr,
 				       entry_attr_timeout(&outarg),
 				       attr_version);

@@ -918,6 +920,7 @@ int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 
 	if (time_before64(fi->i_time, get_jiffies_64())) {
 		r = true;
+		forget_all_cached_acls(inode);
 		err = fuse_do_getattr(inode, stat, file);
 	} else {
 		r = false;

@@ -1065,6 +1068,7 @@ static int fuse_perm_getattr(struct inode *inode, int mask)
 	if (mask & MAY_NOT_BLOCK)
 		return -ECHILD;
 
+	forget_all_cached_acls(inode);
 	return fuse_do_getattr(inode, NULL, NULL);
 }
 

@@ -1234,6 +1238,7 @@ retry:
 		fi->nlookup++;
 		spin_unlock(&fc->lock);
 
+		forget_all_cached_acls(inode);
 		fuse_change_attributes(inode, &o->attr,
 				       entry_attr_timeout(o),
 				       attr_version);

@@ -1703,14 +1708,24 @@ error:
 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(entry);
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	int ret;
 
 	if (!fuse_allow_current_process(get_fuse_conn(inode)))
 		return -EACCES;
 
 	if (attr->ia_valid & ATTR_FILE)
-		return fuse_do_setattr(inode, attr, attr->ia_file);
+		ret = fuse_do_setattr(inode, attr, attr->ia_file);
 	else
-		return fuse_do_setattr(inode, attr, NULL);
+		ret = fuse_do_setattr(inode, attr, NULL);
+
+	/*
+	 * If filesystem supports acls it may have updated acl xattrs in
+	 * the filesystem, so forget cached acls for the inode.
+	 */
+	if (!ret && fc->posix_acl)
+		forget_all_cached_acls(inode);
+	return ret;
 }
 
 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,

@@ -1743,6 +1758,8 @@ static const struct inode_operations fuse_dir_inode_operations = {
 	.getxattr	= generic_getxattr,
 	.listxattr	= fuse_listxattr,
 	.removexattr	= generic_removexattr,
+	.get_acl	= fuse_get_acl,
+	.set_acl	= fuse_set_acl,
 };
 
 static const struct file_operations fuse_dir_operations = {

@@ -1764,6 +1781,8 @@ static const struct inode_operations fuse_common_inode_operations = {
 	.getxattr	= generic_getxattr,
 	.listxattr	= fuse_listxattr,
 	.removexattr	= generic_removexattr,
+	.get_acl	= fuse_get_acl,
+	.set_acl	= fuse_set_acl,
 };
 
 static const struct inode_operations fuse_symlink_inode_operations = {

@@ -1775,6 +1794,8 @@ static const struct inode_operations fuse_symlink_inode_operations = {
 	.getxattr	= generic_getxattr,
 	.listxattr	= fuse_listxattr,
 	.removexattr	= generic_removexattr,
+	.get_acl	= fuse_get_acl,
+	.set_acl	= fuse_set_acl,
 };
 
 void fuse_init_common(struct inode *inode)

@@ -23,6 +23,7 @@
 #include <linux/poll.h>
 #include <linux/workqueue.h>
 #include <linux/kref.h>
+#include <linux/xattr.h>
 
 /** Max number of pages that can be used in a single read request */
 #define FUSE_MAX_PAGES_PER_REQ 32

@@ -624,6 +625,9 @@ struct fuse_conn {
 	/** Is lseek not implemented by fs? */
 	unsigned no_lseek:1;
 
+	/** Does the filesystem support posix acls? */
+	unsigned posix_acl:1;
+
 	/** The number of requests waiting for completion */
 	atomic_t num_waiting;
 

@@ -968,7 +972,21 @@ void fuse_set_initialized(struct fuse_conn *fc);
 void fuse_unlock_inode(struct inode *inode);
 void fuse_lock_inode(struct inode *inode);
 
+int fuse_setxattr(struct inode *inode, const char *name, const void *value,
+		  size_t size, int flags);
+ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
+		      size_t size);
 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
+int fuse_removexattr(struct inode *inode, const char *name);
 extern const struct xattr_handler *fuse_xattr_handlers[];
+extern const struct xattr_handler *fuse_acl_xattr_handlers[];
+
+struct posix_acl;
+
+extern const struct xattr_handler fuse_xattr_acl_access_handler;
+extern const struct xattr_handler fuse_xattr_acl_default_handler;
+
+struct posix_acl *fuse_get_acl(struct inode *inode, int type);
+int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 
 #endif /* _FS_FUSE_I_H */

@@ -20,6 +20,7 @@
 #include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/exportfs.h>
+#include <linux/posix_acl.h>
 
 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
 MODULE_DESCRIPTION("Filesystem in Userspace");

@@ -340,6 +341,7 @@ int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 		return -ENOENT;
 
 	fuse_invalidate_attr(inode);
+	forget_all_cached_acls(inode);
 	if (offset >= 0) {
 		pg_start = offset >> PAGE_SHIFT;
 		if (len <= 0)

@@ -912,6 +914,11 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 				fc->parallel_dirops = 1;
 			if (arg->time_gran && arg->time_gran <= 1000000000)
 				fc->sb->s_time_gran = arg->time_gran;
+			if ((arg->flags & FUSE_POSIX_ACL) &&
+			    (fc->flags & FUSE_DEFAULT_PERMISSIONS)) {
+				fc->posix_acl = 1;
+				fc->sb->s_xattr = fuse_acl_xattr_handlers;
+			}
 		} else {
 			ra_pages = fc->max_read / PAGE_SIZE;
 			fc->no_lock = 1;

@@ -942,6 +949,8 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
 		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
 		FUSE_PARALLEL_DIROPS;
+	if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
+		arg->flags |= FUSE_POSIX_ACL;
 	req->in.h.opcode = FUSE_INIT;
 	req->in.numargs = 1;
 	req->in.args[0].size = sizeof(*arg);

@@ -9,9 +9,10 @@
 #include "fuse_i.h"
 
 #include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
 
-static int fuse_setxattr(struct inode *inode, const char *name,
-			 const void *value, size_t size, int flags)
+int fuse_setxattr(struct inode *inode, const char *name, const void *value,
+		  size_t size, int flags)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	FUSE_ARGS(args);

@@ -45,8 +46,8 @@ static int fuse_setxattr(struct inode *inode, const char *name,
 	return err;
 }
 
-static ssize_t fuse_getxattr(struct inode *inode, const char *name,
-			     void *value, size_t size)
+ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
+		      size_t size)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	FUSE_ARGS(args);

@@ -128,7 +129,7 @@ ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
 	return ret;
 }
 
-static int fuse_removexattr(struct inode *inode, const char *name)
+int fuse_removexattr(struct inode *inode, const char *name)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	FUSE_ARGS(args);

@@ -182,3 +183,10 @@ const struct xattr_handler *fuse_xattr_handlers[] = {
 	&fuse_xattr_handler,
 	NULL
 };
+
+const struct xattr_handler *fuse_acl_xattr_handlers[] = {
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+	&fuse_xattr_handler,
+	NULL
+};

@@ -108,6 +108,7 @@
  *
  *  7.25
  *  - add FUSE_PARALLEL_DIROPS
+ *  - add FUSE_POSIX_ACL
  */
 
 #ifndef _LINUX_FUSE_H

@@ -238,6 +239,7 @@ struct fuse_file_lock {
  * FUSE_WRITEBACK_CACHE: use writeback cache for buffered writes
  * FUSE_NO_OPEN_SUPPORT: kernel supports zero-message opens
  * FUSE_PARALLEL_DIROPS: allow parallel lookups and readdir
+ * FUSE_POSIX_ACL: filesystem supports posix acls
  */
 #define FUSE_ASYNC_READ		(1 << 0)
 #define FUSE_POSIX_LOCKS	(1 << 1)

@@ -258,6 +260,7 @@ struct fuse_file_lock {
 #define FUSE_WRITEBACK_CACHE	(1 << 16)
 #define FUSE_NO_OPEN_SUPPORT	(1 << 17)
 #define FUSE_PARALLEL_DIROPS    (1 << 18)
+#define FUSE_POSIX_ACL		(1 << 19)
 
 /**
  * CUSE INIT request/reply flags