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 == -ENOENT || size == -ENODATA || size == 0) { 59 /* FIXME, who returns -ENOENT? I think nobody */ 60 acl = NULL; 61 } else { 62 acl = ERR_PTR(-EIO); 63 } 64 kfree(value); 65 66 return acl; 67 } 68 69 /* 70 * Needs to be called with fs_mutex held 71 */ 72 static int __btrfs_set_acl(struct btrfs_trans_handle *trans, 73 struct inode *inode, struct posix_acl *acl, int type) 74 { 75 int ret, size = 0; 76 const char *name; 77 char *value = NULL; 78 79 switch (type) { 80 case ACL_TYPE_ACCESS: 81 name = XATTR_NAME_POSIX_ACL_ACCESS; 82 if (acl) { 83 ret = posix_acl_equiv_mode(acl, &inode->i_mode); 84 if (ret < 0) 85 return ret; 86 if (ret == 0) 87 acl = NULL; 88 } 89 ret = 0; 90 break; 91 case ACL_TYPE_DEFAULT: 92 if (!S_ISDIR(inode->i_mode)) 93 return acl ? -EINVAL : 0; 94 name = XATTR_NAME_POSIX_ACL_DEFAULT; 95 break; 96 default: 97 return -EINVAL; 98 } 99 100 if (acl) { 101 size = posix_acl_xattr_size(acl->a_count); 102 value = kmalloc(size, GFP_KERNEL); 103 if (!value) { 104 ret = -ENOMEM; 105 goto out; 106 } 107 108 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size); 109 if (ret < 0) 110 goto out; 111 } 112 113 ret = __btrfs_setxattr(trans, inode, name, value, size, 0); 114 out: 115 kfree(value); 116 117 if (!ret) 118 set_cached_acl(inode, type, acl); 119 120 return ret; 121 } 122 123 int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 124 { 125 return __btrfs_set_acl(NULL, inode, acl, type); 126 } 127 128 /* 129 * btrfs_init_acl is already generally called under fs_mutex, so the locking 130 * stuff has been fixed to work with that. If the locking stuff changes, we 131 * need to re-evaluate the acl locking stuff. 132 */ 133 int btrfs_init_acl(struct btrfs_trans_handle *trans, 134 struct inode *inode, struct inode *dir) 135 { 136 struct posix_acl *default_acl, *acl; 137 int ret = 0; 138 139 /* this happens with subvols */ 140 if (!dir) 141 return 0; 142 143 ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); 144 if (ret) 145 return ret; 146 147 if (default_acl) { 148 ret = __btrfs_set_acl(trans, inode, default_acl, 149 ACL_TYPE_DEFAULT); 150 posix_acl_release(default_acl); 151 } 152 153 if (acl) { 154 if (!ret) 155 ret = __btrfs_set_acl(trans, inode, acl, 156 ACL_TYPE_ACCESS); 157 posix_acl_release(acl); 158 } 159 160 if (!default_acl && !acl) 161 cache_no_acl(inode); 162 return ret; 163 } 164