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 26 #include "ctree.h" 27 #include "btrfs_inode.h" 28 #include "xattr.h" 29 30 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 31 32 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type) 33 { 34 int size; 35 const char *name; 36 char *value = NULL; 37 struct posix_acl *acl; 38 39 acl = get_cached_acl(inode, type); 40 if (acl != ACL_NOT_CACHED) 41 return acl; 42 43 switch (type) { 44 case ACL_TYPE_ACCESS: 45 name = POSIX_ACL_XATTR_ACCESS; 46 break; 47 case ACL_TYPE_DEFAULT: 48 name = POSIX_ACL_XATTR_DEFAULT; 49 break; 50 default: 51 BUG(); 52 } 53 54 size = __btrfs_getxattr(inode, name, "", 0); 55 if (size > 0) { 56 value = kzalloc(size, GFP_NOFS); 57 if (!value) 58 return ERR_PTR(-ENOMEM); 59 size = __btrfs_getxattr(inode, name, value, size); 60 if (size > 0) { 61 acl = posix_acl_from_xattr(value, size); 62 set_cached_acl(inode, type, acl); 63 } 64 kfree(value); 65 } else if (size == -ENOENT || size == -ENODATA || size == 0) { 66 /* FIXME, who returns -ENOENT? I think nobody */ 67 acl = NULL; 68 set_cached_acl(inode, type, acl); 69 } else { 70 acl = ERR_PTR(-EIO); 71 } 72 73 return acl; 74 } 75 76 static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name, 77 void *value, size_t size, int type) 78 { 79 struct posix_acl *acl; 80 int ret = 0; 81 82 acl = btrfs_get_acl(dentry->d_inode, type); 83 84 if (IS_ERR(acl)) 85 return PTR_ERR(acl); 86 if (acl == NULL) 87 return -ENODATA; 88 ret = posix_acl_to_xattr(acl, value, size); 89 posix_acl_release(acl); 90 91 return ret; 92 } 93 94 /* 95 * Needs to be called with fs_mutex held 96 */ 97 static int btrfs_set_acl(struct btrfs_trans_handle *trans, 98 struct inode *inode, struct posix_acl *acl, int type) 99 { 100 int ret, size = 0; 101 const char *name; 102 char *value = NULL; 103 mode_t mode; 104 105 if (acl) { 106 ret = posix_acl_valid(acl); 107 if (ret < 0) 108 return ret; 109 ret = 0; 110 } 111 112 switch (type) { 113 case ACL_TYPE_ACCESS: 114 mode = inode->i_mode; 115 name = POSIX_ACL_XATTR_ACCESS; 116 if (acl) { 117 ret = posix_acl_equiv_mode(acl, &mode); 118 if (ret < 0) 119 return ret; 120 inode->i_mode = mode; 121 } 122 ret = 0; 123 break; 124 case ACL_TYPE_DEFAULT: 125 if (!S_ISDIR(inode->i_mode)) 126 return acl ? -EINVAL : 0; 127 name = POSIX_ACL_XATTR_DEFAULT; 128 break; 129 default: 130 return -EINVAL; 131 } 132 133 if (acl) { 134 size = posix_acl_xattr_size(acl->a_count); 135 value = kmalloc(size, GFP_NOFS); 136 if (!value) { 137 ret = -ENOMEM; 138 goto out; 139 } 140 141 ret = posix_acl_to_xattr(acl, value, size); 142 if (ret < 0) 143 goto out; 144 } 145 146 ret = __btrfs_setxattr(trans, inode, name, value, size, 0); 147 out: 148 kfree(value); 149 150 if (!ret) 151 set_cached_acl(inode, type, acl); 152 153 return ret; 154 } 155 156 static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name, 157 const void *value, size_t size, int flags, int type) 158 { 159 int ret; 160 struct posix_acl *acl = NULL; 161 162 if (value) { 163 acl = posix_acl_from_xattr(value, size); 164 if (acl == NULL) { 165 value = NULL; 166 size = 0; 167 } else if (IS_ERR(acl)) { 168 return PTR_ERR(acl); 169 } 170 } 171 172 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type); 173 174 posix_acl_release(acl); 175 176 return ret; 177 } 178 179 int btrfs_check_acl(struct inode *inode, int mask) 180 { 181 struct posix_acl *acl; 182 int error = -EAGAIN; 183 184 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 185 186 if (IS_ERR(acl)) 187 return PTR_ERR(acl); 188 if (acl) { 189 error = posix_acl_permission(inode, acl, mask); 190 posix_acl_release(acl); 191 } 192 193 return error; 194 } 195 196 /* 197 * btrfs_init_acl is already generally called under fs_mutex, so the locking 198 * stuff has been fixed to work with that. If the locking stuff changes, we 199 * need to re-evaluate the acl locking stuff. 200 */ 201 int btrfs_init_acl(struct btrfs_trans_handle *trans, 202 struct inode *inode, struct inode *dir) 203 { 204 struct posix_acl *acl = NULL; 205 int ret = 0; 206 207 /* this happens with subvols */ 208 if (!dir) 209 return 0; 210 211 if (!S_ISLNK(inode->i_mode)) { 212 if (IS_POSIXACL(dir)) { 213 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 214 if (IS_ERR(acl)) 215 return PTR_ERR(acl); 216 } 217 218 if (!acl) 219 inode->i_mode &= ~current_umask(); 220 } 221 222 if (IS_POSIXACL(dir) && acl) { 223 struct posix_acl *clone; 224 mode_t mode; 225 226 if (S_ISDIR(inode->i_mode)) { 227 ret = btrfs_set_acl(trans, inode, acl, 228 ACL_TYPE_DEFAULT); 229 if (ret) 230 goto failed; 231 } 232 clone = posix_acl_clone(acl, GFP_NOFS); 233 ret = -ENOMEM; 234 if (!clone) 235 goto failed; 236 237 mode = inode->i_mode; 238 ret = posix_acl_create_masq(clone, &mode); 239 if (ret >= 0) { 240 inode->i_mode = mode; 241 if (ret > 0) { 242 /* we need an acl */ 243 ret = btrfs_set_acl(trans, inode, clone, 244 ACL_TYPE_ACCESS); 245 } 246 } 247 posix_acl_release(clone); 248 } 249 failed: 250 posix_acl_release(acl); 251 252 return ret; 253 } 254 255 int btrfs_acl_chmod(struct inode *inode) 256 { 257 struct posix_acl *acl, *clone; 258 int ret = 0; 259 260 if (S_ISLNK(inode->i_mode)) 261 return -EOPNOTSUPP; 262 263 if (!IS_POSIXACL(inode)) 264 return 0; 265 266 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 267 if (IS_ERR(acl) || !acl) 268 return PTR_ERR(acl); 269 270 clone = posix_acl_clone(acl, GFP_KERNEL); 271 posix_acl_release(acl); 272 if (!clone) 273 return -ENOMEM; 274 275 ret = posix_acl_chmod_masq(clone, inode->i_mode); 276 if (!ret) 277 ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS); 278 279 posix_acl_release(clone); 280 281 return ret; 282 } 283 284 struct xattr_handler btrfs_xattr_acl_default_handler = { 285 .prefix = POSIX_ACL_XATTR_DEFAULT, 286 .flags = ACL_TYPE_DEFAULT, 287 .get = btrfs_xattr_acl_get, 288 .set = btrfs_xattr_acl_set, 289 }; 290 291 struct xattr_handler btrfs_xattr_acl_access_handler = { 292 .prefix = POSIX_ACL_XATTR_ACCESS, 293 .flags = ACL_TYPE_ACCESS, 294 .get = btrfs_xattr_acl_get, 295 .set = btrfs_xattr_acl_set, 296 }; 297 298 #else /* CONFIG_BTRFS_FS_POSIX_ACL */ 299 300 int btrfs_acl_chmod(struct inode *inode) 301 { 302 return 0; 303 } 304 305 int btrfs_init_acl(struct btrfs_trans_handle *trans, 306 struct inode *inode, struct inode *dir) 307 { 308 return 0; 309 } 310 311 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */ 312