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_FS_POSIX_ACL 31 32 static void btrfs_update_cached_acl(struct inode *inode, 33 struct posix_acl **p_acl, 34 struct posix_acl *acl) 35 { 36 spin_lock(&inode->i_lock); 37 if (*p_acl && *p_acl != BTRFS_ACL_NOT_CACHED) 38 posix_acl_release(*p_acl); 39 *p_acl = posix_acl_dup(acl); 40 spin_unlock(&inode->i_lock); 41 } 42 43 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type) 44 { 45 int size; 46 const char *name; 47 char *value = NULL; 48 struct posix_acl *acl = NULL, **p_acl; 49 50 switch (type) { 51 case ACL_TYPE_ACCESS: 52 name = POSIX_ACL_XATTR_ACCESS; 53 p_acl = &BTRFS_I(inode)->i_acl; 54 break; 55 case ACL_TYPE_DEFAULT: 56 name = POSIX_ACL_XATTR_DEFAULT; 57 p_acl = &BTRFS_I(inode)->i_default_acl; 58 break; 59 default: 60 return ERR_PTR(-EINVAL); 61 } 62 63 /* Handle the cached NULL acl case without locking */ 64 acl = ACCESS_ONCE(*p_acl); 65 if (!acl) 66 return acl; 67 68 spin_lock(&inode->i_lock); 69 acl = *p_acl; 70 if (acl != BTRFS_ACL_NOT_CACHED) 71 acl = posix_acl_dup(acl); 72 spin_unlock(&inode->i_lock); 73 74 if (acl != BTRFS_ACL_NOT_CACHED) 75 return acl; 76 77 size = __btrfs_getxattr(inode, name, "", 0); 78 if (size > 0) { 79 value = kzalloc(size, GFP_NOFS); 80 if (!value) 81 return ERR_PTR(-ENOMEM); 82 size = __btrfs_getxattr(inode, name, value, size); 83 if (size > 0) { 84 acl = posix_acl_from_xattr(value, size); 85 btrfs_update_cached_acl(inode, p_acl, acl); 86 } 87 kfree(value); 88 } else if (size == -ENOENT || size == -ENODATA || size == 0) { 89 /* FIXME, who returns -ENOENT? I think nobody */ 90 acl = NULL; 91 btrfs_update_cached_acl(inode, p_acl, acl); 92 } else { 93 acl = ERR_PTR(-EIO); 94 } 95 96 return acl; 97 } 98 99 static int btrfs_xattr_get_acl(struct inode *inode, int type, 100 void *value, size_t size) 101 { 102 struct posix_acl *acl; 103 int ret = 0; 104 105 acl = btrfs_get_acl(inode, type); 106 107 if (IS_ERR(acl)) 108 return PTR_ERR(acl); 109 if (acl == NULL) 110 return -ENODATA; 111 ret = posix_acl_to_xattr(acl, value, size); 112 posix_acl_release(acl); 113 114 return ret; 115 } 116 117 /* 118 * Needs to be called with fs_mutex held 119 */ 120 static int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 121 { 122 int ret, size = 0; 123 const char *name; 124 struct posix_acl **p_acl; 125 char *value = NULL; 126 mode_t mode; 127 128 if (acl) { 129 ret = posix_acl_valid(acl); 130 if (ret < 0) 131 return ret; 132 ret = 0; 133 } 134 135 switch (type) { 136 case ACL_TYPE_ACCESS: 137 mode = inode->i_mode; 138 ret = posix_acl_equiv_mode(acl, &mode); 139 if (ret < 0) 140 return ret; 141 ret = 0; 142 inode->i_mode = mode; 143 name = POSIX_ACL_XATTR_ACCESS; 144 p_acl = &BTRFS_I(inode)->i_acl; 145 break; 146 case ACL_TYPE_DEFAULT: 147 if (!S_ISDIR(inode->i_mode)) 148 return acl ? -EINVAL : 0; 149 name = POSIX_ACL_XATTR_DEFAULT; 150 p_acl = &BTRFS_I(inode)->i_default_acl; 151 break; 152 default: 153 return -EINVAL; 154 } 155 156 if (acl) { 157 size = posix_acl_xattr_size(acl->a_count); 158 value = kmalloc(size, GFP_NOFS); 159 if (!value) { 160 ret = -ENOMEM; 161 goto out; 162 } 163 164 ret = posix_acl_to_xattr(acl, value, size); 165 if (ret < 0) 166 goto out; 167 } 168 169 ret = __btrfs_setxattr(inode, name, value, size, 0); 170 171 out: 172 kfree(value); 173 174 if (!ret) 175 btrfs_update_cached_acl(inode, p_acl, acl); 176 177 return ret; 178 } 179 180 static int btrfs_xattr_set_acl(struct inode *inode, int type, 181 const void *value, size_t size) 182 { 183 int ret = 0; 184 struct posix_acl *acl = NULL; 185 186 if (value) { 187 acl = posix_acl_from_xattr(value, size); 188 if (acl == NULL) { 189 value = NULL; 190 size = 0; 191 } else if (IS_ERR(acl)) { 192 return PTR_ERR(acl); 193 } 194 } 195 196 ret = btrfs_set_acl(inode, acl, type); 197 198 posix_acl_release(acl); 199 200 return ret; 201 } 202 203 204 static int btrfs_xattr_acl_access_get(struct inode *inode, const char *name, 205 void *value, size_t size) 206 { 207 return btrfs_xattr_get_acl(inode, ACL_TYPE_ACCESS, value, size); 208 } 209 210 static int btrfs_xattr_acl_access_set(struct inode *inode, const char *name, 211 const void *value, size_t size, int flags) 212 { 213 return btrfs_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size); 214 } 215 216 static int btrfs_xattr_acl_default_get(struct inode *inode, const char *name, 217 void *value, size_t size) 218 { 219 return btrfs_xattr_get_acl(inode, ACL_TYPE_DEFAULT, value, size); 220 } 221 222 static int btrfs_xattr_acl_default_set(struct inode *inode, const char *name, 223 const void *value, size_t size, int flags) 224 { 225 return btrfs_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size); 226 } 227 228 int btrfs_check_acl(struct inode *inode, int mask) 229 { 230 struct posix_acl *acl; 231 int error = -EAGAIN; 232 233 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 234 235 if (IS_ERR(acl)) 236 return PTR_ERR(acl); 237 if (acl) { 238 error = posix_acl_permission(inode, acl, mask); 239 posix_acl_release(acl); 240 } 241 242 return error; 243 } 244 245 /* 246 * btrfs_init_acl is already generally called under fs_mutex, so the locking 247 * stuff has been fixed to work with that. If the locking stuff changes, we 248 * need to re-evaluate the acl locking stuff. 249 */ 250 int btrfs_init_acl(struct inode *inode, struct inode *dir) 251 { 252 struct posix_acl *acl = NULL; 253 int ret = 0; 254 255 /* this happens with subvols */ 256 if (!dir) 257 return 0; 258 259 if (!S_ISLNK(inode->i_mode)) { 260 if (IS_POSIXACL(dir)) { 261 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 262 if (IS_ERR(acl)) 263 return PTR_ERR(acl); 264 } 265 266 if (!acl) 267 inode->i_mode &= ~current_umask(); 268 } 269 270 if (IS_POSIXACL(dir) && acl) { 271 struct posix_acl *clone; 272 mode_t mode; 273 274 if (S_ISDIR(inode->i_mode)) { 275 ret = btrfs_set_acl(inode, acl, ACL_TYPE_DEFAULT); 276 if (ret) 277 goto failed; 278 } 279 clone = posix_acl_clone(acl, GFP_NOFS); 280 ret = -ENOMEM; 281 if (!clone) 282 goto failed; 283 284 mode = inode->i_mode; 285 ret = posix_acl_create_masq(clone, &mode); 286 if (ret >= 0) { 287 inode->i_mode = mode; 288 if (ret > 0) { 289 /* we need an acl */ 290 ret = btrfs_set_acl(inode, clone, 291 ACL_TYPE_ACCESS); 292 } 293 } 294 } 295 failed: 296 posix_acl_release(acl); 297 298 return ret; 299 } 300 301 int btrfs_acl_chmod(struct inode *inode) 302 { 303 struct posix_acl *acl, *clone; 304 int ret = 0; 305 306 if (S_ISLNK(inode->i_mode)) 307 return -EOPNOTSUPP; 308 309 if (!IS_POSIXACL(inode)) 310 return 0; 311 312 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 313 if (IS_ERR(acl) || !acl) 314 return PTR_ERR(acl); 315 316 clone = posix_acl_clone(acl, GFP_KERNEL); 317 posix_acl_release(acl); 318 if (!clone) 319 return -ENOMEM; 320 321 ret = posix_acl_chmod_masq(clone, inode->i_mode); 322 if (!ret) 323 ret = btrfs_set_acl(inode, clone, ACL_TYPE_ACCESS); 324 325 posix_acl_release(clone); 326 327 return ret; 328 } 329 330 struct xattr_handler btrfs_xattr_acl_default_handler = { 331 .prefix = POSIX_ACL_XATTR_DEFAULT, 332 .get = btrfs_xattr_acl_default_get, 333 .set = btrfs_xattr_acl_default_set, 334 }; 335 336 struct xattr_handler btrfs_xattr_acl_access_handler = { 337 .prefix = POSIX_ACL_XATTR_ACCESS, 338 .get = btrfs_xattr_acl_access_get, 339 .set = btrfs_xattr_acl_access_set, 340 }; 341 342 #else /* CONFIG_FS_POSIX_ACL */ 343 344 int btrfs_acl_chmod(struct inode *inode) 345 { 346 return 0; 347 } 348 349 int btrfs_init_acl(struct inode *inode, struct inode *dir) 350 { 351 return 0; 352 } 353 354 int btrfs_check_acl(struct inode *inode, int mask) 355 { 356 return 0; 357 } 358 359 #endif /* CONFIG_FS_POSIX_ACL */ 360