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 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 32 33 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type) 34 { 35 int size; 36 const char *name; 37 char *value = NULL; 38 struct posix_acl *acl; 39 40 acl = get_cached_acl(inode, type); 41 if (acl != ACL_NOT_CACHED) 42 return acl; 43 44 switch (type) { 45 case ACL_TYPE_ACCESS: 46 name = POSIX_ACL_XATTR_ACCESS; 47 break; 48 case ACL_TYPE_DEFAULT: 49 name = POSIX_ACL_XATTR_DEFAULT; 50 break; 51 default: 52 BUG(); 53 } 54 55 size = __btrfs_getxattr(inode, name, "", 0); 56 if (size > 0) { 57 value = kzalloc(size, GFP_NOFS); 58 if (!value) 59 return ERR_PTR(-ENOMEM); 60 size = __btrfs_getxattr(inode, name, value, size); 61 if (size > 0) { 62 acl = posix_acl_from_xattr(value, size); 63 set_cached_acl(inode, type, acl); 64 } 65 kfree(value); 66 } else if (size == -ENOENT || size == -ENODATA || size == 0) { 67 /* FIXME, who returns -ENOENT? I think nobody */ 68 acl = NULL; 69 set_cached_acl(inode, type, acl); 70 } else { 71 acl = ERR_PTR(-EIO); 72 } 73 74 return acl; 75 } 76 77 static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name, 78 void *value, size_t size, int type) 79 { 80 struct posix_acl *acl; 81 int ret = 0; 82 83 acl = btrfs_get_acl(dentry->d_inode, type); 84 85 if (IS_ERR(acl)) 86 return PTR_ERR(acl); 87 if (acl == NULL) 88 return -ENODATA; 89 ret = posix_acl_to_xattr(acl, value, size); 90 posix_acl_release(acl); 91 92 return ret; 93 } 94 95 /* 96 * Needs to be called with fs_mutex held 97 */ 98 static int btrfs_set_acl(struct btrfs_trans_handle *trans, 99 struct inode *inode, struct posix_acl *acl, int type) 100 { 101 int ret, size = 0; 102 const char *name; 103 char *value = NULL; 104 mode_t mode; 105 106 if (acl) { 107 ret = posix_acl_valid(acl); 108 if (ret < 0) 109 return ret; 110 ret = 0; 111 } 112 113 switch (type) { 114 case ACL_TYPE_ACCESS: 115 mode = inode->i_mode; 116 name = POSIX_ACL_XATTR_ACCESS; 117 if (acl) { 118 ret = posix_acl_equiv_mode(acl, &mode); 119 if (ret < 0) 120 return ret; 121 inode->i_mode = mode; 122 } 123 ret = 0; 124 break; 125 case ACL_TYPE_DEFAULT: 126 if (!S_ISDIR(inode->i_mode)) 127 return acl ? -EINVAL : 0; 128 name = POSIX_ACL_XATTR_DEFAULT; 129 break; 130 default: 131 return -EINVAL; 132 } 133 134 if (acl) { 135 size = posix_acl_xattr_size(acl->a_count); 136 value = kmalloc(size, GFP_NOFS); 137 if (!value) { 138 ret = -ENOMEM; 139 goto out; 140 } 141 142 ret = posix_acl_to_xattr(acl, value, size); 143 if (ret < 0) 144 goto out; 145 } 146 147 ret = __btrfs_setxattr(trans, inode, name, value, size, 0); 148 out: 149 kfree(value); 150 151 if (!ret) 152 set_cached_acl(inode, type, acl); 153 154 return ret; 155 } 156 157 static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name, 158 const void *value, size_t size, int flags, int type) 159 { 160 int ret; 161 struct posix_acl *acl = NULL; 162 163 if (value) { 164 acl = posix_acl_from_xattr(value, size); 165 if (acl == NULL) { 166 value = NULL; 167 size = 0; 168 } else if (IS_ERR(acl)) { 169 return PTR_ERR(acl); 170 } 171 } 172 173 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type); 174 175 posix_acl_release(acl); 176 177 return ret; 178 } 179 180 int btrfs_check_acl(struct inode *inode, int mask) 181 { 182 struct posix_acl *acl; 183 int error = -EAGAIN; 184 185 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 186 187 if (IS_ERR(acl)) 188 return PTR_ERR(acl); 189 if (acl) { 190 error = posix_acl_permission(inode, acl, mask); 191 posix_acl_release(acl); 192 } 193 194 return error; 195 } 196 197 /* 198 * btrfs_init_acl is already generally called under fs_mutex, so the locking 199 * stuff has been fixed to work with that. If the locking stuff changes, we 200 * need to re-evaluate the acl locking stuff. 201 */ 202 int btrfs_init_acl(struct btrfs_trans_handle *trans, 203 struct inode *inode, struct inode *dir) 204 { 205 struct posix_acl *acl = NULL; 206 int ret = 0; 207 208 /* this happens with subvols */ 209 if (!dir) 210 return 0; 211 212 if (!S_ISLNK(inode->i_mode)) { 213 if (IS_POSIXACL(dir)) { 214 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 215 if (IS_ERR(acl)) 216 return PTR_ERR(acl); 217 } 218 219 if (!acl) 220 inode->i_mode &= ~current_umask(); 221 } 222 223 if (IS_POSIXACL(dir) && acl) { 224 struct posix_acl *clone; 225 mode_t mode; 226 227 if (S_ISDIR(inode->i_mode)) { 228 ret = btrfs_set_acl(trans, inode, acl, 229 ACL_TYPE_DEFAULT); 230 if (ret) 231 goto failed; 232 } 233 clone = posix_acl_clone(acl, GFP_NOFS); 234 ret = -ENOMEM; 235 if (!clone) 236 goto failed; 237 238 mode = inode->i_mode; 239 ret = posix_acl_create_masq(clone, &mode); 240 if (ret >= 0) { 241 inode->i_mode = mode; 242 if (ret > 0) { 243 /* we need an acl */ 244 ret = btrfs_set_acl(trans, inode, clone, 245 ACL_TYPE_ACCESS); 246 } 247 } 248 posix_acl_release(clone); 249 } 250 failed: 251 posix_acl_release(acl); 252 253 return ret; 254 } 255 256 int btrfs_acl_chmod(struct inode *inode) 257 { 258 struct posix_acl *acl, *clone; 259 int ret = 0; 260 261 if (S_ISLNK(inode->i_mode)) 262 return -EOPNOTSUPP; 263 264 if (!IS_POSIXACL(inode)) 265 return 0; 266 267 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 268 if (IS_ERR(acl) || !acl) 269 return PTR_ERR(acl); 270 271 clone = posix_acl_clone(acl, GFP_KERNEL); 272 posix_acl_release(acl); 273 if (!clone) 274 return -ENOMEM; 275 276 ret = posix_acl_chmod_masq(clone, inode->i_mode); 277 if (!ret) 278 ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS); 279 280 posix_acl_release(clone); 281 282 return ret; 283 } 284 285 struct xattr_handler btrfs_xattr_acl_default_handler = { 286 .prefix = POSIX_ACL_XATTR_DEFAULT, 287 .flags = ACL_TYPE_DEFAULT, 288 .get = btrfs_xattr_acl_get, 289 .set = btrfs_xattr_acl_set, 290 }; 291 292 struct xattr_handler btrfs_xattr_acl_access_handler = { 293 .prefix = POSIX_ACL_XATTR_ACCESS, 294 .flags = ACL_TYPE_ACCESS, 295 .get = btrfs_xattr_acl_get, 296 .set = btrfs_xattr_acl_set, 297 }; 298 299 #else /* CONFIG_BTRFS_FS_POSIX_ACL */ 300 301 int btrfs_acl_chmod(struct inode *inode) 302 { 303 return 0; 304 } 305 306 int btrfs_init_acl(struct btrfs_trans_handle *trans, 307 struct inode *inode, struct inode *dir) 308 { 309 return 0; 310 } 311 312 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */ 313