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/init.h> 20 #include <linux/fs.h> 21 #include <linux/slab.h> 22 #include <linux/rwsem.h> 23 #include <linux/xattr.h> 24 #include "ctree.h" 25 #include "btrfs_inode.h" 26 #include "transaction.h" 27 #include "xattr.h" 28 #include "disk-io.h" 29 30 31 ssize_t __btrfs_getxattr(struct inode *inode, const char *name, 32 void *buffer, size_t size) 33 { 34 struct btrfs_dir_item *di; 35 struct btrfs_root *root = BTRFS_I(inode)->root; 36 struct btrfs_path *path; 37 struct extent_buffer *leaf; 38 int ret = 0; 39 unsigned long data_ptr; 40 41 path = btrfs_alloc_path(); 42 if (!path) 43 return -ENOMEM; 44 45 /* lookup the xattr by name */ 46 di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name, 47 strlen(name), 0); 48 if (!di || IS_ERR(di)) { 49 ret = -ENODATA; 50 goto out; 51 } 52 53 leaf = path->nodes[0]; 54 /* if size is 0, that means we want the size of the attr */ 55 if (!size) { 56 ret = btrfs_dir_data_len(leaf, di); 57 goto out; 58 } 59 60 /* now get the data out of our dir_item */ 61 if (btrfs_dir_data_len(leaf, di) > size) { 62 ret = -ERANGE; 63 goto out; 64 } 65 data_ptr = (unsigned long)((char *)(di + 1) + 66 btrfs_dir_name_len(leaf, di)); 67 read_extent_buffer(leaf, buffer, data_ptr, 68 btrfs_dir_data_len(leaf, di)); 69 ret = btrfs_dir_data_len(leaf, di); 70 71 out: 72 btrfs_free_path(path); 73 return ret; 74 } 75 76 int __btrfs_setxattr(struct inode *inode, const char *name, 77 const void *value, size_t size, int flags) 78 { 79 struct btrfs_dir_item *di; 80 struct btrfs_root *root = BTRFS_I(inode)->root; 81 struct btrfs_trans_handle *trans; 82 struct btrfs_path *path; 83 int ret = 0, mod = 0; 84 85 path = btrfs_alloc_path(); 86 if (!path) 87 return -ENOMEM; 88 89 trans = btrfs_start_transaction(root, 1); 90 btrfs_set_trans_block_group(trans, inode); 91 92 /* first lets see if we already have this xattr */ 93 di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name, 94 strlen(name), -1); 95 if (IS_ERR(di)) { 96 ret = PTR_ERR(di); 97 goto out; 98 } 99 100 /* ok we already have this xattr, lets remove it */ 101 if (di) { 102 /* if we want create only exit */ 103 if (flags & XATTR_CREATE) { 104 ret = -EEXIST; 105 goto out; 106 } 107 108 ret = btrfs_delete_one_dir_name(trans, root, path, di); 109 if (ret) 110 goto out; 111 btrfs_release_path(root, path); 112 113 /* if we don't have a value then we are removing the xattr */ 114 if (!value) { 115 mod = 1; 116 goto out; 117 } 118 } else { 119 btrfs_release_path(root, path); 120 121 if (flags & XATTR_REPLACE) { 122 /* we couldn't find the attr to replace */ 123 ret = -ENODATA; 124 goto out; 125 } 126 } 127 128 /* ok we have to create a completely new xattr */ 129 ret = btrfs_insert_xattr_item(trans, root, name, strlen(name), 130 value, size, inode->i_ino); 131 if (ret) 132 goto out; 133 mod = 1; 134 135 out: 136 if (mod) { 137 inode->i_ctime = CURRENT_TIME; 138 ret = btrfs_update_inode(trans, root, inode); 139 } 140 141 btrfs_end_transaction(trans, root); 142 btrfs_free_path(path); 143 return ret; 144 } 145 146 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) 147 { 148 struct btrfs_key key, found_key; 149 struct inode *inode = dentry->d_inode; 150 struct btrfs_root *root = BTRFS_I(inode)->root; 151 struct btrfs_path *path; 152 struct btrfs_item *item; 153 struct extent_buffer *leaf; 154 struct btrfs_dir_item *di; 155 int ret = 0, slot, advance; 156 size_t total_size = 0, size_left = size; 157 unsigned long name_ptr; 158 size_t name_len; 159 u32 nritems; 160 161 /* 162 * ok we want all objects associated with this id. 163 * NOTE: we set key.offset = 0; because we want to start with the 164 * first xattr that we find and walk forward 165 */ 166 key.objectid = inode->i_ino; 167 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); 168 key.offset = 0; 169 170 path = btrfs_alloc_path(); 171 if (!path) 172 return -ENOMEM; 173 path->reada = 2; 174 175 /* search for our xattrs */ 176 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 177 if (ret < 0) 178 goto err; 179 ret = 0; 180 advance = 0; 181 while (1) { 182 leaf = path->nodes[0]; 183 nritems = btrfs_header_nritems(leaf); 184 slot = path->slots[0]; 185 186 /* this is where we start walking through the path */ 187 if (advance || slot >= nritems) { 188 /* 189 * if we've reached the last slot in this leaf we need 190 * to go to the next leaf and reset everything 191 */ 192 if (slot >= nritems-1) { 193 ret = btrfs_next_leaf(root, path); 194 if (ret) 195 break; 196 leaf = path->nodes[0]; 197 nritems = btrfs_header_nritems(leaf); 198 slot = path->slots[0]; 199 } else { 200 /* 201 * just walking through the slots on this leaf 202 */ 203 slot++; 204 path->slots[0]++; 205 } 206 } 207 advance = 1; 208 209 item = btrfs_item_nr(leaf, slot); 210 btrfs_item_key_to_cpu(leaf, &found_key, slot); 211 212 /* check to make sure this item is what we want */ 213 if (found_key.objectid != key.objectid) 214 break; 215 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY) 216 break; 217 218 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); 219 220 name_len = btrfs_dir_name_len(leaf, di); 221 total_size += name_len + 1; 222 223 /* we are just looking for how big our buffer needs to be */ 224 if (!size) 225 continue; 226 227 if (!buffer || (name_len + 1) > size_left) { 228 ret = -ERANGE; 229 break; 230 } 231 232 name_ptr = (unsigned long)(di + 1); 233 read_extent_buffer(leaf, buffer, name_ptr, name_len); 234 buffer[name_len] = '\0'; 235 236 size_left -= name_len + 1; 237 buffer += name_len + 1; 238 } 239 ret = total_size; 240 241 err: 242 btrfs_free_path(path); 243 244 return ret; 245 } 246 247 /* 248 * List of handlers for synthetic system.* attributes. All real ondisk 249 * attributes are handled directly. 250 */ 251 struct xattr_handler *btrfs_xattr_handlers[] = { 252 #ifdef CONFIG_FS_POSIX_ACL 253 &btrfs_xattr_acl_access_handler, 254 &btrfs_xattr_acl_default_handler, 255 #endif 256 NULL, 257 }; 258 259 /* 260 * Check if the attribute is in a supported namespace. 261 * 262 * This applied after the check for the synthetic attributes in the system 263 * namespace. 264 */ 265 static bool btrfs_is_valid_xattr(const char *name) 266 { 267 return !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || 268 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || 269 !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || 270 !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); 271 } 272 273 ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, 274 void *buffer, size_t size) 275 { 276 /* 277 * If this is a request for a synthetic attribute in the system.* 278 * namespace use the generic infrastructure to resolve a handler 279 * for it via sb->s_xattr. 280 */ 281 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) 282 return generic_getxattr(dentry, name, buffer, size); 283 284 if (!btrfs_is_valid_xattr(name)) 285 return -EOPNOTSUPP; 286 return __btrfs_getxattr(dentry->d_inode, name, buffer, size); 287 } 288 289 int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, 290 size_t size, int flags) 291 { 292 /* 293 * If this is a request for a synthetic attribute in the system.* 294 * namespace use the generic infrastructure to resolve a handler 295 * for it via sb->s_xattr. 296 */ 297 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) 298 return generic_setxattr(dentry, name, value, size, flags); 299 300 if (!btrfs_is_valid_xattr(name)) 301 return -EOPNOTSUPP; 302 303 if (size == 0) 304 value = ""; /* empty EA, do not remove */ 305 return __btrfs_setxattr(dentry->d_inode, name, value, size, flags); 306 } 307 308 int btrfs_removexattr(struct dentry *dentry, const char *name) 309 { 310 /* 311 * If this is a request for a synthetic attribute in the system.* 312 * namespace use the generic infrastructure to resolve a handler 313 * for it via sb->s_xattr. 314 */ 315 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) 316 return generic_removexattr(dentry, name); 317 318 if (!btrfs_is_valid_xattr(name)) 319 return -EOPNOTSUPP; 320 return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE); 321 } 322