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_get_acl(struct inode *inode, int type, 77 void *value, size_t size) 78 { 79 struct posix_acl *acl; 80 int ret = 0; 81 82 acl = btrfs_get_acl(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 inode *inode, struct posix_acl *acl, int type) 98 { 99 int ret, size = 0; 100 const char *name; 101 char *value = NULL; 102 mode_t mode; 103 104 if (acl) { 105 ret = posix_acl_valid(acl); 106 if (ret < 0) 107 return ret; 108 ret = 0; 109 } 110 111 switch (type) { 112 case ACL_TYPE_ACCESS: 113 mode = inode->i_mode; 114 ret = posix_acl_equiv_mode(acl, &mode); 115 if (ret < 0) 116 return ret; 117 ret = 0; 118 inode->i_mode = mode; 119 name = POSIX_ACL_XATTR_ACCESS; 120 break; 121 case ACL_TYPE_DEFAULT: 122 if (!S_ISDIR(inode->i_mode)) 123 return acl ? -EINVAL : 0; 124 name = POSIX_ACL_XATTR_DEFAULT; 125 break; 126 default: 127 return -EINVAL; 128 } 129 130 if (acl) { 131 size = posix_acl_xattr_size(acl->a_count); 132 value = kmalloc(size, GFP_NOFS); 133 if (!value) { 134 ret = -ENOMEM; 135 goto out; 136 } 137 138 ret = posix_acl_to_xattr(acl, value, size); 139 if (ret < 0) 140 goto out; 141 } 142 143 ret = __btrfs_setxattr(inode, name, value, size, 0); 144 145 out: 146 kfree(value); 147 148 if (!ret) 149 set_cached_acl(inode, type, acl); 150 151 return ret; 152 } 153 154 static int btrfs_xattr_set_acl(struct inode *inode, int type, 155 const void *value, size_t size) 156 { 157 int ret = 0; 158 struct posix_acl *acl = NULL; 159 160 if (value) { 161 acl = posix_acl_from_xattr(value, size); 162 if (acl == NULL) { 163 value = NULL; 164 size = 0; 165 } else if (IS_ERR(acl)) { 166 return PTR_ERR(acl); 167 } 168 } 169 170 ret = btrfs_set_acl(inode, acl, type); 171 172 posix_acl_release(acl); 173 174 return ret; 175 } 176 177 178 static int btrfs_xattr_acl_access_get(struct inode *inode, const char *name, 179 void *value, size_t size) 180 { 181 return btrfs_xattr_get_acl(inode, ACL_TYPE_ACCESS, value, size); 182 } 183 184 static int btrfs_xattr_acl_access_set(struct inode *inode, const char *name, 185 const void *value, size_t size, int flags) 186 { 187 return btrfs_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size); 188 } 189 190 static int btrfs_xattr_acl_default_get(struct inode *inode, const char *name, 191 void *value, size_t size) 192 { 193 return btrfs_xattr_get_acl(inode, ACL_TYPE_DEFAULT, value, size); 194 } 195 196 static int btrfs_xattr_acl_default_set(struct inode *inode, const char *name, 197 const void *value, size_t size, int flags) 198 { 199 return btrfs_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size); 200 } 201 202 int btrfs_check_acl(struct inode *inode, int mask) 203 { 204 struct posix_acl *acl; 205 int error = -EAGAIN; 206 207 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 208 209 if (IS_ERR(acl)) 210 return PTR_ERR(acl); 211 if (acl) { 212 error = posix_acl_permission(inode, acl, mask); 213 posix_acl_release(acl); 214 } 215 216 return error; 217 } 218 219 /* 220 * btrfs_init_acl is already generally called under fs_mutex, so the locking 221 * stuff has been fixed to work with that. If the locking stuff changes, we 222 * need to re-evaluate the acl locking stuff. 223 */ 224 int btrfs_init_acl(struct inode *inode, struct inode *dir) 225 { 226 struct posix_acl *acl = NULL; 227 int ret = 0; 228 229 /* this happens with subvols */ 230 if (!dir) 231 return 0; 232 233 if (!S_ISLNK(inode->i_mode)) { 234 if (IS_POSIXACL(dir)) { 235 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 236 if (IS_ERR(acl)) 237 return PTR_ERR(acl); 238 } 239 240 if (!acl) 241 inode->i_mode &= ~current_umask(); 242 } 243 244 if (IS_POSIXACL(dir) && acl) { 245 struct posix_acl *clone; 246 mode_t mode; 247 248 if (S_ISDIR(inode->i_mode)) { 249 ret = btrfs_set_acl(inode, acl, ACL_TYPE_DEFAULT); 250 if (ret) 251 goto failed; 252 } 253 clone = posix_acl_clone(acl, GFP_NOFS); 254 ret = -ENOMEM; 255 if (!clone) 256 goto failed; 257 258 mode = inode->i_mode; 259 ret = posix_acl_create_masq(clone, &mode); 260 if (ret >= 0) { 261 inode->i_mode = mode; 262 if (ret > 0) { 263 /* we need an acl */ 264 ret = btrfs_set_acl(inode, clone, 265 ACL_TYPE_ACCESS); 266 } 267 } 268 } 269 failed: 270 posix_acl_release(acl); 271 272 return ret; 273 } 274 275 int btrfs_acl_chmod(struct inode *inode) 276 { 277 struct posix_acl *acl, *clone; 278 int ret = 0; 279 280 if (S_ISLNK(inode->i_mode)) 281 return -EOPNOTSUPP; 282 283 if (!IS_POSIXACL(inode)) 284 return 0; 285 286 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 287 if (IS_ERR(acl) || !acl) 288 return PTR_ERR(acl); 289 290 clone = posix_acl_clone(acl, GFP_KERNEL); 291 posix_acl_release(acl); 292 if (!clone) 293 return -ENOMEM; 294 295 ret = posix_acl_chmod_masq(clone, inode->i_mode); 296 if (!ret) 297 ret = btrfs_set_acl(inode, clone, ACL_TYPE_ACCESS); 298 299 posix_acl_release(clone); 300 301 return ret; 302 } 303 304 struct xattr_handler btrfs_xattr_acl_default_handler = { 305 .prefix = POSIX_ACL_XATTR_DEFAULT, 306 .get = btrfs_xattr_acl_default_get, 307 .set = btrfs_xattr_acl_default_set, 308 }; 309 310 struct xattr_handler btrfs_xattr_acl_access_handler = { 311 .prefix = POSIX_ACL_XATTR_ACCESS, 312 .get = btrfs_xattr_acl_access_get, 313 .set = btrfs_xattr_acl_access_set, 314 }; 315 316 #else /* CONFIG_BTRFS_FS_POSIX_ACL */ 317 318 int btrfs_acl_chmod(struct inode *inode) 319 { 320 return 0; 321 } 322 323 int btrfs_init_acl(struct inode *inode, struct inode *dir) 324 { 325 return 0; 326 } 327 328 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */ 329