1 /* 2 * Copyright (C) 2007 Red Hat. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include <linux/fs.h> 20 #include <linux/string.h> 21 #include <linux/xattr.h> 22 #include <linux/posix_acl_xattr.h> 23 #include <linux/posix_acl.h> 24 #include <linux/sched.h> 25 #include <linux/slab.h> 26 27 #include "ctree.h" 28 #include "btrfs_inode.h" 29 #include "xattr.h" 30 31 struct posix_acl *btrfs_get_acl(struct inode *inode, int type) 32 { 33 int size; 34 const char *name; 35 char *value = NULL; 36 struct posix_acl *acl; 37 38 switch (type) { 39 case ACL_TYPE_ACCESS: 40 name = XATTR_NAME_POSIX_ACL_ACCESS; 41 break; 42 case ACL_TYPE_DEFAULT: 43 name = XATTR_NAME_POSIX_ACL_DEFAULT; 44 break; 45 default: 46 BUG(); 47 } 48 49 size = __btrfs_getxattr(inode, name, "", 0); 50 if (size > 0) { 51 value = kzalloc(size, GFP_KERNEL); 52 if (!value) 53 return ERR_PTR(-ENOMEM); 54 size = __btrfs_getxattr(inode, name, value, size); 55 } 56 if (size > 0) { 57 acl = posix_acl_from_xattr(&init_user_ns, value, size); 58 } else if (size == -ERANGE || size == -ENODATA || size == 0) { 59 acl = NULL; 60 } else { 61 acl = ERR_PTR(-EIO); 62 } 63 kfree(value); 64 65 return acl; 66 } 67 68 /* 69 * Needs to be called with fs_mutex held 70 */ 71 static int __btrfs_set_acl(struct btrfs_trans_handle *trans, 72 struct inode *inode, struct posix_acl *acl, int type) 73 { 74 int ret, size = 0; 75 const char *name; 76 char *value = NULL; 77 78 switch (type) { 79 case ACL_TYPE_ACCESS: 80 name = XATTR_NAME_POSIX_ACL_ACCESS; 81 if (acl) { 82 ret = posix_acl_equiv_mode(acl, &inode->i_mode); 83 if (ret < 0) 84 return ret; 85 if (ret == 0) 86 acl = NULL; 87 } 88 ret = 0; 89 break; 90 case ACL_TYPE_DEFAULT: 91 if (!S_ISDIR(inode->i_mode)) 92 return acl ? -EINVAL : 0; 93 name = XATTR_NAME_POSIX_ACL_DEFAULT; 94 break; 95 default: 96 return -EINVAL; 97 } 98 99 if (acl) { 100 size = posix_acl_xattr_size(acl->a_count); 101 value = kmalloc(size, GFP_KERNEL); 102 if (!value) { 103 ret = -ENOMEM; 104 goto out; 105 } 106 107 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size); 108 if (ret < 0) 109 goto out; 110 } 111 112 ret = __btrfs_setxattr(trans, inode, name, value, size, 0); 113 out: 114 kfree(value); 115 116 if (!ret) 117 set_cached_acl(inode, type, acl); 118 119 return ret; 120 } 121 122 int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 123 { 124 return __btrfs_set_acl(NULL, inode, acl, type); 125 } 126 127 /* 128 * btrfs_init_acl is already generally called under fs_mutex, so the locking 129 * stuff has been fixed to work with that. If the locking stuff changes, we 130 * need to re-evaluate the acl locking stuff. 131 */ 132 int btrfs_init_acl(struct btrfs_trans_handle *trans, 133 struct inode *inode, struct inode *dir) 134 { 135 struct posix_acl *default_acl, *acl; 136 int ret = 0; 137 138 /* this happens with subvols */ 139 if (!dir) 140 return 0; 141 142 ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); 143 if (ret) 144 return ret; 145 146 if (default_acl) { 147 ret = __btrfs_set_acl(trans, inode, default_acl, 148 ACL_TYPE_DEFAULT); 149 posix_acl_release(default_acl); 150 } 151 152 if (acl) { 153 if (!ret) 154 ret = __btrfs_set_acl(trans, inode, acl, 155 ACL_TYPE_ACCESS); 156 posix_acl_release(acl); 157 } 158 159 if (!default_acl && !acl) 160 cache_no_acl(inode); 161 return ret; 162 } 163