1 files changed, 53 insertions, 208 deletions

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index e15d2b0d8d3b..c336e2ab7f8a 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -1,19 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2007 Red Hat.  All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
  */
 
 #include <linux/fs.h>
@@ -22,258 +9,116 @@
 #include <linux/posix_acl_xattr.h>
 #include <linux/posix_acl.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/slab.h>
-
 #include "ctree.h"
-#include "btrfs_inode.h"
 #include "xattr.h"
+#include "acl.h"
+#include "misc.h"
 
-struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
+struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu)
 {
 	int size;
 	const char *name;
-	char *value = NULL;
+	char AUTO_KFREE(value);
 	struct posix_acl *acl;
 
-	if (!IS_POSIXACL(inode))
-		return NULL;
-
-	acl = get_cached_acl(inode, type);
-	if (acl != ACL_NOT_CACHED)
-		return acl;
+	if (rcu)
+		return ERR_PTR(-ECHILD);
 
 	switch (type) {
 	case ACL_TYPE_ACCESS:
-		name = POSIX_ACL_XATTR_ACCESS;
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
 		break;
 	case ACL_TYPE_DEFAULT:
-		name = POSIX_ACL_XATTR_DEFAULT;
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
 		break;
 	default:
-		BUG();
+		return ERR_PTR(-EINVAL);
 	}
 
-	size = __btrfs_getxattr(inode, name, "", 0);
+	size = btrfs_getxattr(inode, name, NULL, 0);
 	if (size > 0) {
-		value = kzalloc(size, GFP_NOFS);
+		value = kzalloc(size, GFP_KERNEL);
 		if (!value)
 			return ERR_PTR(-ENOMEM);
-		size = __btrfs_getxattr(inode, name, value, size);
+		size = btrfs_getxattr(inode, name, value, size);
 	}
-	if (size > 0) {
+	if (size > 0)
 		acl = posix_acl_from_xattr(&init_user_ns, value, size);
-	} else if (size == -ENOENT || size == -ENODATA || size == 0) {
-		/* FIXME, who returns -ENOENT?  I think nobody */
+	else if (size == -ENODATA || size == 0)
 		acl = NULL;
-	} else {
-		acl = ERR_PTR(-EIO);
-	}
-	kfree(value);
-
-	if (!IS_ERR(acl))
-		set_cached_acl(inode, type, acl);
+	else
+		acl = ERR_PTR(size);
 
 	return acl;
 }
 
-static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name,
-		void *value, size_t size, int type)
-{
-	struct posix_acl *acl;
-	int ret = 0;
-
-	if (!IS_POSIXACL(dentry->d_inode))
-		return -EOPNOTSUPP;
-
-	acl = btrfs_get_acl(dentry->d_inode, type);
-
-	if (IS_ERR(acl))
-		return PTR_ERR(acl);
-	if (acl == NULL)
-		return -ENODATA;
-	ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
-	posix_acl_release(acl);
-
-	return ret;
-}
-
-/*
- * Needs to be called with fs_mutex held
- */
-static int btrfs_set_acl(struct btrfs_trans_handle *trans,
-			 struct inode *inode, struct posix_acl *acl, int type)
+int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode,
+		    struct posix_acl *acl, int type)
 {
 	int ret, size = 0;
 	const char *name;
-	char *value = NULL;
-
-	if (acl) {
-		ret = posix_acl_valid(acl);
-		if (ret < 0)
-			return ret;
-		ret = 0;
-	}
+	char AUTO_KFREE(value);
 
 	switch (type) {
 	case ACL_TYPE_ACCESS:
-		name = POSIX_ACL_XATTR_ACCESS;
-		if (acl) {
-			ret = posix_acl_equiv_mode(acl, &inode->i_mode);
-			if (ret < 0)
-				return ret;
-			if (ret == 0)
-				acl = NULL;
-		}
-		ret = 0;
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
 		break;
 	case ACL_TYPE_DEFAULT:
 		if (!S_ISDIR(inode->i_mode))
 			return acl ? -EINVAL : 0;
-		name = POSIX_ACL_XATTR_DEFAULT;
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
 		break;
 	default:
 		return -EINVAL;
 	}
 
 	if (acl) {
+		unsigned int nofs_flag;
+
 		size = posix_acl_xattr_size(acl->a_count);
-		value = kmalloc(size, GFP_NOFS);
-		if (!value) {
-			ret = -ENOMEM;
-			goto out;
-		}
+		/*
+		 * We're holding a transaction handle, so use a NOFS memory
+		 * allocation context to avoid deadlock if reclaim happens.
+		 */
+		nofs_flag = memalloc_nofs_save();
+		value = kmalloc(size, GFP_KERNEL);
+		memalloc_nofs_restore(nofs_flag);
+		if (!value)
+			return -ENOMEM;
 
 		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 		if (ret < 0)
-			goto out;
+			return ret;
 	}
 
-	ret = __btrfs_setxattr(trans, inode, name, value, size, 0);
-out:
-	kfree(value);
-
-	if (!ret)
-		set_cached_acl(inode, type, acl);
+	if (trans)
+		ret = btrfs_setxattr(trans, inode, name, value, size, 0);
+	else
+		ret = btrfs_setxattr_trans(inode, name, value, size, 0);
+	if (ret < 0)
+		return ret;
 
-	return ret;
+	set_cached_acl(inode, type, acl);
+	return 0;
 }
 
-static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
-		const void *value, size_t size, int flags, int type)
+int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		  struct posix_acl *acl, int type)
 {
 	int ret;
-	struct posix_acl *acl = NULL;
-
-	if (!inode_owner_or_capable(dentry->d_inode))
-		return -EPERM;
-
-	if (!IS_POSIXACL(dentry->d_inode))
-		return -EOPNOTSUPP;
-
-	if (value) {
-		acl = posix_acl_from_xattr(&init_user_ns, value, size);
-		if (IS_ERR(acl))
-			return PTR_ERR(acl);
-
-		if (acl) {
-			ret = posix_acl_valid(acl);
-			if (ret)
-				goto out;
-		}
-	}
-
-	ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type);
-out:
-	posix_acl_release(acl);
-
-	return ret;
-}
-
-/*
- * btrfs_init_acl is already generally called under fs_mutex, so the locking
- * stuff has been fixed to work with that.  If the locking stuff changes, we
- * need to re-evaluate the acl locking stuff.
- */
-int btrfs_init_acl(struct btrfs_trans_handle *trans,
-		   struct inode *inode, struct inode *dir)
-{
-	struct posix_acl *acl = NULL;
-	int ret = 0;
-
-	/* this happens with subvols */
-	if (!dir)
-		return 0;
-
-	if (!S_ISLNK(inode->i_mode)) {
-		if (IS_POSIXACL(dir)) {
-			acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
-			if (IS_ERR(acl))
-				return PTR_ERR(acl);
-		}
-
-		if (!acl)
-			inode->i_mode &= ~current_umask();
-	}
+	struct inode *inode = d_inode(dentry);
+	umode_t old_mode = inode->i_mode;
 
-	if (IS_POSIXACL(dir) && acl) {
-		if (S_ISDIR(inode->i_mode)) {
-			ret = btrfs_set_acl(trans, inode, acl,
-					    ACL_TYPE_DEFAULT);
-			if (ret)
-				goto failed;
-		}
-		ret = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
-		if (ret < 0)
+	if (type == ACL_TYPE_ACCESS && acl) {
+		ret = posix_acl_update_mode(idmap, inode,
+					    &inode->i_mode, &acl);
+		if (ret)
 			return ret;
-
-		if (ret > 0) {
-			/* we need an acl */
-			ret = btrfs_set_acl(trans, inode, acl, ACL_TYPE_ACCESS);
-		} else {
-			cache_no_acl(inode);
-		}
-	} else {
-		cache_no_acl(inode);
 	}
-failed:
-	posix_acl_release(acl);
-
-	return ret;
-}
-
-int btrfs_acl_chmod(struct inode *inode)
-{
-	struct posix_acl *acl;
-	int ret = 0;
-
-	if (S_ISLNK(inode->i_mode))
-		return -EOPNOTSUPP;
-
-	if (!IS_POSIXACL(inode))
-		return 0;
-
-	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
-	if (IS_ERR_OR_NULL(acl))
-		return PTR_ERR(acl);
-
-	ret = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
+	ret = __btrfs_set_acl(NULL, inode, acl, type);
 	if (ret)
-		return ret;
-	ret = btrfs_set_acl(NULL, inode, acl, ACL_TYPE_ACCESS);
-	posix_acl_release(acl);
+		inode->i_mode = old_mode;
 	return ret;
 }
-
-const struct xattr_handler btrfs_xattr_acl_default_handler = {
-	.prefix = POSIX_ACL_XATTR_DEFAULT,
-	.flags	= ACL_TYPE_DEFAULT,
-	.get	= btrfs_xattr_acl_get,
-	.set	= btrfs_xattr_acl_set,
-};
-
-const struct xattr_handler btrfs_xattr_acl_access_handler = {
-	.prefix = POSIX_ACL_XATTR_ACCESS,
-	.flags	= ACL_TYPE_ACCESS,
-	.get	= btrfs_xattr_acl_get,
-	.set	= btrfs_xattr_acl_set,
-};