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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2007 Red Hat. All rights reserved.4 */5 6#include <linux/fs.h>7#include <linux/string.h>8#include <linux/xattr.h>9#include <linux/posix_acl_xattr.h>10#include <linux/posix_acl.h>11#include <linux/sched.h>12#include <linux/sched/mm.h>13#include <linux/slab.h>14#include "ctree.h"15#include "xattr.h"16#include "acl.h"17 18struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu)19{20 int size;21 const char *name;22 char *value = NULL;23 struct posix_acl *acl;24 25 if (rcu)26 return ERR_PTR(-ECHILD);27 28 switch (type) {29 case ACL_TYPE_ACCESS:30 name = XATTR_NAME_POSIX_ACL_ACCESS;31 break;32 case ACL_TYPE_DEFAULT:33 name = XATTR_NAME_POSIX_ACL_DEFAULT;34 break;35 default:36 return ERR_PTR(-EINVAL);37 }38 39 size = btrfs_getxattr(inode, name, NULL, 0);40 if (size > 0) {41 value = kzalloc(size, GFP_KERNEL);42 if (!value)43 return ERR_PTR(-ENOMEM);44 size = btrfs_getxattr(inode, name, value, size);45 }46 if (size > 0)47 acl = posix_acl_from_xattr(&init_user_ns, value, size);48 else if (size == -ENODATA || size == 0)49 acl = NULL;50 else51 acl = ERR_PTR(size);52 kfree(value);53 54 return acl;55}56 57int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode,58 struct posix_acl *acl, int type)59{60 int ret, size = 0;61 const char *name;62 char *value = NULL;63 64 switch (type) {65 case ACL_TYPE_ACCESS:66 name = XATTR_NAME_POSIX_ACL_ACCESS;67 break;68 case ACL_TYPE_DEFAULT:69 if (!S_ISDIR(inode->i_mode))70 return acl ? -EINVAL : 0;71 name = XATTR_NAME_POSIX_ACL_DEFAULT;72 break;73 default:74 return -EINVAL;75 }76 77 if (acl) {78 unsigned int nofs_flag;79 80 size = posix_acl_xattr_size(acl->a_count);81 /*82 * We're holding a transaction handle, so use a NOFS memory83 * allocation context to avoid deadlock if reclaim happens.84 */85 nofs_flag = memalloc_nofs_save();86 value = kmalloc(size, GFP_KERNEL);87 memalloc_nofs_restore(nofs_flag);88 if (!value) {89 ret = -ENOMEM;90 goto out;91 }92 93 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);94 if (ret < 0)95 goto out;96 }97 98 if (trans)99 ret = btrfs_setxattr(trans, inode, name, value, size, 0);100 else101 ret = btrfs_setxattr_trans(inode, name, value, size, 0);102 103out:104 kfree(value);105 106 if (!ret)107 set_cached_acl(inode, type, acl);108 109 return ret;110}111 112int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,113 struct posix_acl *acl, int type)114{115 int ret;116 struct inode *inode = d_inode(dentry);117 umode_t old_mode = inode->i_mode;118 119 if (type == ACL_TYPE_ACCESS && acl) {120 ret = posix_acl_update_mode(idmap, inode,121 &inode->i_mode, &acl);122 if (ret)123 return ret;124 }125 ret = __btrfs_set_acl(NULL, inode, acl, type);126 if (ret)127 inode->i_mode = old_mode;128 return ret;129}130