| 1 | /* |
| 2 | * Copyright (C) 2007,2008 Oracle. 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/sched.h> |
| 20 | #include <linux/slab.h> |
| 21 | #include <linux/rbtree.h> |
| 22 | #include "ctree.h" |
| 23 | #include "disk-io.h" |
| 24 | #include "transaction.h" |
| 25 | #include "print-tree.h" |
| 26 | #include "locking.h" |
| 27 | |
| 28 | static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
| 29 | *root, struct btrfs_path *path, int level); |
| 30 | static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root |
| 31 | *root, struct btrfs_key *ins_key, |
| 32 | struct btrfs_path *path, int data_size, int extend); |
| 33 | static int push_node_left(struct btrfs_trans_handle *trans, |
| 34 | struct btrfs_root *root, struct extent_buffer *dst, |
| 35 | struct extent_buffer *src, int empty); |
| 36 | static int balance_node_right(struct btrfs_trans_handle *trans, |
| 37 | struct btrfs_root *root, |
| 38 | struct extent_buffer *dst_buf, |
| 39 | struct extent_buffer *src_buf); |
| 40 | static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 41 | struct btrfs_path *path, int level, int slot); |
| 42 | static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, |
| 43 | struct extent_buffer *eb); |
| 44 | struct extent_buffer *read_old_tree_block(struct btrfs_root *root, u64 bytenr, |
| 45 | u32 blocksize, u64 parent_transid, |
| 46 | u64 time_seq); |
| 47 | struct extent_buffer *btrfs_find_old_tree_block(struct btrfs_root *root, |
| 48 | u64 bytenr, u32 blocksize, |
| 49 | u64 time_seq); |
| 50 | |
| 51 | struct btrfs_path *btrfs_alloc_path(void) |
| 52 | { |
| 53 | struct btrfs_path *path; |
| 54 | path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); |
| 55 | return path; |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * set all locked nodes in the path to blocking locks. This should |
| 60 | * be done before scheduling |
| 61 | */ |
| 62 | noinline void btrfs_set_path_blocking(struct btrfs_path *p) |
| 63 | { |
| 64 | int i; |
| 65 | for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
| 66 | if (!p->nodes[i] || !p->locks[i]) |
| 67 | continue; |
| 68 | btrfs_set_lock_blocking_rw(p->nodes[i], p->locks[i]); |
| 69 | if (p->locks[i] == BTRFS_READ_LOCK) |
| 70 | p->locks[i] = BTRFS_READ_LOCK_BLOCKING; |
| 71 | else if (p->locks[i] == BTRFS_WRITE_LOCK) |
| 72 | p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING; |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | /* |
| 77 | * reset all the locked nodes in the patch to spinning locks. |
| 78 | * |
| 79 | * held is used to keep lockdep happy, when lockdep is enabled |
| 80 | * we set held to a blocking lock before we go around and |
| 81 | * retake all the spinlocks in the path. You can safely use NULL |
| 82 | * for held |
| 83 | */ |
| 84 | noinline void btrfs_clear_path_blocking(struct btrfs_path *p, |
| 85 | struct extent_buffer *held, int held_rw) |
| 86 | { |
| 87 | int i; |
| 88 | |
| 89 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 90 | /* lockdep really cares that we take all of these spinlocks |
| 91 | * in the right order. If any of the locks in the path are not |
| 92 | * currently blocking, it is going to complain. So, make really |
| 93 | * really sure by forcing the path to blocking before we clear |
| 94 | * the path blocking. |
| 95 | */ |
| 96 | if (held) { |
| 97 | btrfs_set_lock_blocking_rw(held, held_rw); |
| 98 | if (held_rw == BTRFS_WRITE_LOCK) |
| 99 | held_rw = BTRFS_WRITE_LOCK_BLOCKING; |
| 100 | else if (held_rw == BTRFS_READ_LOCK) |
| 101 | held_rw = BTRFS_READ_LOCK_BLOCKING; |
| 102 | } |
| 103 | btrfs_set_path_blocking(p); |
| 104 | #endif |
| 105 | |
| 106 | for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) { |
| 107 | if (p->nodes[i] && p->locks[i]) { |
| 108 | btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]); |
| 109 | if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING) |
| 110 | p->locks[i] = BTRFS_WRITE_LOCK; |
| 111 | else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING) |
| 112 | p->locks[i] = BTRFS_READ_LOCK; |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 117 | if (held) |
| 118 | btrfs_clear_lock_blocking_rw(held, held_rw); |
| 119 | #endif |
| 120 | } |
| 121 | |
| 122 | /* this also releases the path */ |
| 123 | void btrfs_free_path(struct btrfs_path *p) |
| 124 | { |
| 125 | if (!p) |
| 126 | return; |
| 127 | btrfs_release_path(p); |
| 128 | kmem_cache_free(btrfs_path_cachep, p); |
| 129 | } |
| 130 | |
| 131 | /* |
| 132 | * path release drops references on the extent buffers in the path |
| 133 | * and it drops any locks held by this path |
| 134 | * |
| 135 | * It is safe to call this on paths that no locks or extent buffers held. |
| 136 | */ |
| 137 | noinline void btrfs_release_path(struct btrfs_path *p) |
| 138 | { |
| 139 | int i; |
| 140 | |
| 141 | for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
| 142 | p->slots[i] = 0; |
| 143 | if (!p->nodes[i]) |
| 144 | continue; |
| 145 | if (p->locks[i]) { |
| 146 | btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]); |
| 147 | p->locks[i] = 0; |
| 148 | } |
| 149 | free_extent_buffer(p->nodes[i]); |
| 150 | p->nodes[i] = NULL; |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | /* |
| 155 | * safely gets a reference on the root node of a tree. A lock |
| 156 | * is not taken, so a concurrent writer may put a different node |
| 157 | * at the root of the tree. See btrfs_lock_root_node for the |
| 158 | * looping required. |
| 159 | * |
| 160 | * The extent buffer returned by this has a reference taken, so |
| 161 | * it won't disappear. It may stop being the root of the tree |
| 162 | * at any time because there are no locks held. |
| 163 | */ |
| 164 | struct extent_buffer *btrfs_root_node(struct btrfs_root *root) |
| 165 | { |
| 166 | struct extent_buffer *eb; |
| 167 | |
| 168 | while (1) { |
| 169 | rcu_read_lock(); |
| 170 | eb = rcu_dereference(root->node); |
| 171 | |
| 172 | /* |
| 173 | * RCU really hurts here, we could free up the root node because |
| 174 | * it was cow'ed but we may not get the new root node yet so do |
| 175 | * the inc_not_zero dance and if it doesn't work then |
| 176 | * synchronize_rcu and try again. |
| 177 | */ |
| 178 | if (atomic_inc_not_zero(&eb->refs)) { |
| 179 | rcu_read_unlock(); |
| 180 | break; |
| 181 | } |
| 182 | rcu_read_unlock(); |
| 183 | synchronize_rcu(); |
| 184 | } |
| 185 | return eb; |
| 186 | } |
| 187 | |
| 188 | /* loop around taking references on and locking the root node of the |
| 189 | * tree until you end up with a lock on the root. A locked buffer |
| 190 | * is returned, with a reference held. |
| 191 | */ |
| 192 | struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root) |
| 193 | { |
| 194 | struct extent_buffer *eb; |
| 195 | |
| 196 | while (1) { |
| 197 | eb = btrfs_root_node(root); |
| 198 | btrfs_tree_lock(eb); |
| 199 | if (eb == root->node) |
| 200 | break; |
| 201 | btrfs_tree_unlock(eb); |
| 202 | free_extent_buffer(eb); |
| 203 | } |
| 204 | return eb; |
| 205 | } |
| 206 | |
| 207 | /* loop around taking references on and locking the root node of the |
| 208 | * tree until you end up with a lock on the root. A locked buffer |
| 209 | * is returned, with a reference held. |
| 210 | */ |
| 211 | struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root) |
| 212 | { |
| 213 | struct extent_buffer *eb; |
| 214 | |
| 215 | while (1) { |
| 216 | eb = btrfs_root_node(root); |
| 217 | btrfs_tree_read_lock(eb); |
| 218 | if (eb == root->node) |
| 219 | break; |
| 220 | btrfs_tree_read_unlock(eb); |
| 221 | free_extent_buffer(eb); |
| 222 | } |
| 223 | return eb; |
| 224 | } |
| 225 | |
| 226 | /* cowonly root (everything not a reference counted cow subvolume), just get |
| 227 | * put onto a simple dirty list. transaction.c walks this to make sure they |
| 228 | * get properly updated on disk. |
| 229 | */ |
| 230 | static void add_root_to_dirty_list(struct btrfs_root *root) |
| 231 | { |
| 232 | spin_lock(&root->fs_info->trans_lock); |
| 233 | if (root->track_dirty && list_empty(&root->dirty_list)) { |
| 234 | list_add(&root->dirty_list, |
| 235 | &root->fs_info->dirty_cowonly_roots); |
| 236 | } |
| 237 | spin_unlock(&root->fs_info->trans_lock); |
| 238 | } |
| 239 | |
| 240 | /* |
| 241 | * used by snapshot creation to make a copy of a root for a tree with |
| 242 | * a given objectid. The buffer with the new root node is returned in |
| 243 | * cow_ret, and this func returns zero on success or a negative error code. |
| 244 | */ |
| 245 | int btrfs_copy_root(struct btrfs_trans_handle *trans, |
| 246 | struct btrfs_root *root, |
| 247 | struct extent_buffer *buf, |
| 248 | struct extent_buffer **cow_ret, u64 new_root_objectid) |
| 249 | { |
| 250 | struct extent_buffer *cow; |
| 251 | int ret = 0; |
| 252 | int level; |
| 253 | struct btrfs_disk_key disk_key; |
| 254 | |
| 255 | WARN_ON(root->ref_cows && trans->transid != |
| 256 | root->fs_info->running_transaction->transid); |
| 257 | WARN_ON(root->ref_cows && trans->transid != root->last_trans); |
| 258 | |
| 259 | level = btrfs_header_level(buf); |
| 260 | if (level == 0) |
| 261 | btrfs_item_key(buf, &disk_key, 0); |
| 262 | else |
| 263 | btrfs_node_key(buf, &disk_key, 0); |
| 264 | |
| 265 | cow = btrfs_alloc_free_block(trans, root, buf->len, 0, |
| 266 | new_root_objectid, &disk_key, level, |
| 267 | buf->start, 0); |
| 268 | if (IS_ERR(cow)) |
| 269 | return PTR_ERR(cow); |
| 270 | |
| 271 | copy_extent_buffer(cow, buf, 0, 0, cow->len); |
| 272 | btrfs_set_header_bytenr(cow, cow->start); |
| 273 | btrfs_set_header_generation(cow, trans->transid); |
| 274 | btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
| 275 | btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
| 276 | BTRFS_HEADER_FLAG_RELOC); |
| 277 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
| 278 | btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
| 279 | else |
| 280 | btrfs_set_header_owner(cow, new_root_objectid); |
| 281 | |
| 282 | write_extent_buffer(cow, root->fs_info->fsid, |
| 283 | (unsigned long)btrfs_header_fsid(cow), |
| 284 | BTRFS_FSID_SIZE); |
| 285 | |
| 286 | WARN_ON(btrfs_header_generation(buf) > trans->transid); |
| 287 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
| 288 | ret = btrfs_inc_ref(trans, root, cow, 1, 1); |
| 289 | else |
| 290 | ret = btrfs_inc_ref(trans, root, cow, 0, 1); |
| 291 | |
| 292 | if (ret) |
| 293 | return ret; |
| 294 | |
| 295 | btrfs_mark_buffer_dirty(cow); |
| 296 | *cow_ret = cow; |
| 297 | return 0; |
| 298 | } |
| 299 | |
| 300 | enum mod_log_op { |
| 301 | MOD_LOG_KEY_REPLACE, |
| 302 | MOD_LOG_KEY_ADD, |
| 303 | MOD_LOG_KEY_REMOVE, |
| 304 | MOD_LOG_KEY_REMOVE_WHILE_FREEING, |
| 305 | MOD_LOG_KEY_REMOVE_WHILE_MOVING, |
| 306 | MOD_LOG_MOVE_KEYS, |
| 307 | MOD_LOG_ROOT_REPLACE, |
| 308 | }; |
| 309 | |
| 310 | struct tree_mod_move { |
| 311 | int dst_slot; |
| 312 | int nr_items; |
| 313 | }; |
| 314 | |
| 315 | struct tree_mod_root { |
| 316 | u64 logical; |
| 317 | u8 level; |
| 318 | }; |
| 319 | |
| 320 | struct tree_mod_elem { |
| 321 | struct rb_node node; |
| 322 | u64 index; /* shifted logical */ |
| 323 | u64 seq; |
| 324 | enum mod_log_op op; |
| 325 | |
| 326 | /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */ |
| 327 | int slot; |
| 328 | |
| 329 | /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */ |
| 330 | u64 generation; |
| 331 | |
| 332 | /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */ |
| 333 | struct btrfs_disk_key key; |
| 334 | u64 blockptr; |
| 335 | |
| 336 | /* this is used for op == MOD_LOG_MOVE_KEYS */ |
| 337 | struct tree_mod_move move; |
| 338 | |
| 339 | /* this is used for op == MOD_LOG_ROOT_REPLACE */ |
| 340 | struct tree_mod_root old_root; |
| 341 | }; |
| 342 | |
| 343 | static inline void tree_mod_log_read_lock(struct btrfs_fs_info *fs_info) |
| 344 | { |
| 345 | read_lock(&fs_info->tree_mod_log_lock); |
| 346 | } |
| 347 | |
| 348 | static inline void tree_mod_log_read_unlock(struct btrfs_fs_info *fs_info) |
| 349 | { |
| 350 | read_unlock(&fs_info->tree_mod_log_lock); |
| 351 | } |
| 352 | |
| 353 | static inline void tree_mod_log_write_lock(struct btrfs_fs_info *fs_info) |
| 354 | { |
| 355 | write_lock(&fs_info->tree_mod_log_lock); |
| 356 | } |
| 357 | |
| 358 | static inline void tree_mod_log_write_unlock(struct btrfs_fs_info *fs_info) |
| 359 | { |
| 360 | write_unlock(&fs_info->tree_mod_log_lock); |
| 361 | } |
| 362 | |
| 363 | /* |
| 364 | * This adds a new blocker to the tree mod log's blocker list if the @elem |
| 365 | * passed does not already have a sequence number set. So when a caller expects |
| 366 | * to record tree modifications, it should ensure to set elem->seq to zero |
| 367 | * before calling btrfs_get_tree_mod_seq. |
| 368 | * Returns a fresh, unused tree log modification sequence number, even if no new |
| 369 | * blocker was added. |
| 370 | */ |
| 371 | u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info, |
| 372 | struct seq_list *elem) |
| 373 | { |
| 374 | u64 seq; |
| 375 | |
| 376 | tree_mod_log_write_lock(fs_info); |
| 377 | spin_lock(&fs_info->tree_mod_seq_lock); |
| 378 | if (!elem->seq) { |
| 379 | elem->seq = btrfs_inc_tree_mod_seq(fs_info); |
| 380 | list_add_tail(&elem->list, &fs_info->tree_mod_seq_list); |
| 381 | } |
| 382 | seq = btrfs_inc_tree_mod_seq(fs_info); |
| 383 | spin_unlock(&fs_info->tree_mod_seq_lock); |
| 384 | tree_mod_log_write_unlock(fs_info); |
| 385 | |
| 386 | return seq; |
| 387 | } |
| 388 | |
| 389 | void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info, |
| 390 | struct seq_list *elem) |
| 391 | { |
| 392 | struct rb_root *tm_root; |
| 393 | struct rb_node *node; |
| 394 | struct rb_node *next; |
| 395 | struct seq_list *cur_elem; |
| 396 | struct tree_mod_elem *tm; |
| 397 | u64 min_seq = (u64)-1; |
| 398 | u64 seq_putting = elem->seq; |
| 399 | |
| 400 | if (!seq_putting) |
| 401 | return; |
| 402 | |
| 403 | spin_lock(&fs_info->tree_mod_seq_lock); |
| 404 | list_del(&elem->list); |
| 405 | elem->seq = 0; |
| 406 | |
| 407 | list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) { |
| 408 | if (cur_elem->seq < min_seq) { |
| 409 | if (seq_putting > cur_elem->seq) { |
| 410 | /* |
| 411 | * blocker with lower sequence number exists, we |
| 412 | * cannot remove anything from the log |
| 413 | */ |
| 414 | spin_unlock(&fs_info->tree_mod_seq_lock); |
| 415 | return; |
| 416 | } |
| 417 | min_seq = cur_elem->seq; |
| 418 | } |
| 419 | } |
| 420 | spin_unlock(&fs_info->tree_mod_seq_lock); |
| 421 | |
| 422 | /* |
| 423 | * anything that's lower than the lowest existing (read: blocked) |
| 424 | * sequence number can be removed from the tree. |
| 425 | */ |
| 426 | tree_mod_log_write_lock(fs_info); |
| 427 | tm_root = &fs_info->tree_mod_log; |
| 428 | for (node = rb_first(tm_root); node; node = next) { |
| 429 | next = rb_next(node); |
| 430 | tm = container_of(node, struct tree_mod_elem, node); |
| 431 | if (tm->seq > min_seq) |
| 432 | continue; |
| 433 | rb_erase(node, tm_root); |
| 434 | kfree(tm); |
| 435 | } |
| 436 | tree_mod_log_write_unlock(fs_info); |
| 437 | } |
| 438 | |
| 439 | /* |
| 440 | * key order of the log: |
| 441 | * index -> sequence |
| 442 | * |
| 443 | * the index is the shifted logical of the *new* root node for root replace |
| 444 | * operations, or the shifted logical of the affected block for all other |
| 445 | * operations. |
| 446 | */ |
| 447 | static noinline int |
| 448 | __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm) |
| 449 | { |
| 450 | struct rb_root *tm_root; |
| 451 | struct rb_node **new; |
| 452 | struct rb_node *parent = NULL; |
| 453 | struct tree_mod_elem *cur; |
| 454 | |
| 455 | BUG_ON(!tm || !tm->seq); |
| 456 | |
| 457 | tm_root = &fs_info->tree_mod_log; |
| 458 | new = &tm_root->rb_node; |
| 459 | while (*new) { |
| 460 | cur = container_of(*new, struct tree_mod_elem, node); |
| 461 | parent = *new; |
| 462 | if (cur->index < tm->index) |
| 463 | new = &((*new)->rb_left); |
| 464 | else if (cur->index > tm->index) |
| 465 | new = &((*new)->rb_right); |
| 466 | else if (cur->seq < tm->seq) |
| 467 | new = &((*new)->rb_left); |
| 468 | else if (cur->seq > tm->seq) |
| 469 | new = &((*new)->rb_right); |
| 470 | else { |
| 471 | kfree(tm); |
| 472 | return -EEXIST; |
| 473 | } |
| 474 | } |
| 475 | |
| 476 | rb_link_node(&tm->node, parent, new); |
| 477 | rb_insert_color(&tm->node, tm_root); |
| 478 | return 0; |
| 479 | } |
| 480 | |
| 481 | /* |
| 482 | * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it |
| 483 | * returns zero with the tree_mod_log_lock acquired. The caller must hold |
| 484 | * this until all tree mod log insertions are recorded in the rb tree and then |
| 485 | * call tree_mod_log_write_unlock() to release. |
| 486 | */ |
| 487 | static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info, |
| 488 | struct extent_buffer *eb) { |
| 489 | smp_mb(); |
| 490 | if (list_empty(&(fs_info)->tree_mod_seq_list)) |
| 491 | return 1; |
| 492 | if (eb && btrfs_header_level(eb) == 0) |
| 493 | return 1; |
| 494 | |
| 495 | tree_mod_log_write_lock(fs_info); |
| 496 | if (list_empty(&fs_info->tree_mod_seq_list)) { |
| 497 | /* |
| 498 | * someone emptied the list while we were waiting for the lock. |
| 499 | * we must not add to the list when no blocker exists. |
| 500 | */ |
| 501 | tree_mod_log_write_unlock(fs_info); |
| 502 | return 1; |
| 503 | } |
| 504 | |
| 505 | return 0; |
| 506 | } |
| 507 | |
| 508 | /* |
| 509 | * This allocates memory and gets a tree modification sequence number. |
| 510 | * |
| 511 | * Returns <0 on error. |
| 512 | * Returns >0 (the added sequence number) on success. |
| 513 | */ |
| 514 | static inline int tree_mod_alloc(struct btrfs_fs_info *fs_info, gfp_t flags, |
| 515 | struct tree_mod_elem **tm_ret) |
| 516 | { |
| 517 | struct tree_mod_elem *tm; |
| 518 | |
| 519 | /* |
| 520 | * once we switch from spin locks to something different, we should |
| 521 | * honor the flags parameter here. |
| 522 | */ |
| 523 | tm = *tm_ret = kzalloc(sizeof(*tm), GFP_ATOMIC); |
| 524 | if (!tm) |
| 525 | return -ENOMEM; |
| 526 | |
| 527 | tm->seq = btrfs_inc_tree_mod_seq(fs_info); |
| 528 | return tm->seq; |
| 529 | } |
| 530 | |
| 531 | static inline int |
| 532 | __tree_mod_log_insert_key(struct btrfs_fs_info *fs_info, |
| 533 | struct extent_buffer *eb, int slot, |
| 534 | enum mod_log_op op, gfp_t flags) |
| 535 | { |
| 536 | int ret; |
| 537 | struct tree_mod_elem *tm; |
| 538 | |
| 539 | ret = tree_mod_alloc(fs_info, flags, &tm); |
| 540 | if (ret < 0) |
| 541 | return ret; |
| 542 | |
| 543 | tm->index = eb->start >> PAGE_CACHE_SHIFT; |
| 544 | if (op != MOD_LOG_KEY_ADD) { |
| 545 | btrfs_node_key(eb, &tm->key, slot); |
| 546 | tm->blockptr = btrfs_node_blockptr(eb, slot); |
| 547 | } |
| 548 | tm->op = op; |
| 549 | tm->slot = slot; |
| 550 | tm->generation = btrfs_node_ptr_generation(eb, slot); |
| 551 | |
| 552 | return __tree_mod_log_insert(fs_info, tm); |
| 553 | } |
| 554 | |
| 555 | static noinline int |
| 556 | tree_mod_log_insert_key_mask(struct btrfs_fs_info *fs_info, |
| 557 | struct extent_buffer *eb, int slot, |
| 558 | enum mod_log_op op, gfp_t flags) |
| 559 | { |
| 560 | int ret; |
| 561 | |
| 562 | if (tree_mod_dont_log(fs_info, eb)) |
| 563 | return 0; |
| 564 | |
| 565 | ret = __tree_mod_log_insert_key(fs_info, eb, slot, op, flags); |
| 566 | |
| 567 | tree_mod_log_write_unlock(fs_info); |
| 568 | return ret; |
| 569 | } |
| 570 | |
| 571 | static noinline int |
| 572 | tree_mod_log_insert_key(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, |
| 573 | int slot, enum mod_log_op op) |
| 574 | { |
| 575 | return tree_mod_log_insert_key_mask(fs_info, eb, slot, op, GFP_NOFS); |
| 576 | } |
| 577 | |
| 578 | static noinline int |
| 579 | tree_mod_log_insert_key_locked(struct btrfs_fs_info *fs_info, |
| 580 | struct extent_buffer *eb, int slot, |
| 581 | enum mod_log_op op) |
| 582 | { |
| 583 | return __tree_mod_log_insert_key(fs_info, eb, slot, op, GFP_NOFS); |
| 584 | } |
| 585 | |
| 586 | static noinline int |
| 587 | tree_mod_log_insert_move(struct btrfs_fs_info *fs_info, |
| 588 | struct extent_buffer *eb, int dst_slot, int src_slot, |
| 589 | int nr_items, gfp_t flags) |
| 590 | { |
| 591 | struct tree_mod_elem *tm; |
| 592 | int ret; |
| 593 | int i; |
| 594 | |
| 595 | if (tree_mod_dont_log(fs_info, eb)) |
| 596 | return 0; |
| 597 | |
| 598 | /* |
| 599 | * When we override something during the move, we log these removals. |
| 600 | * This can only happen when we move towards the beginning of the |
| 601 | * buffer, i.e. dst_slot < src_slot. |
| 602 | */ |
| 603 | for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) { |
| 604 | ret = tree_mod_log_insert_key_locked(fs_info, eb, i + dst_slot, |
| 605 | MOD_LOG_KEY_REMOVE_WHILE_MOVING); |
| 606 | BUG_ON(ret < 0); |
| 607 | } |
| 608 | |
| 609 | ret = tree_mod_alloc(fs_info, flags, &tm); |
| 610 | if (ret < 0) |
| 611 | goto out; |
| 612 | |
| 613 | tm->index = eb->start >> PAGE_CACHE_SHIFT; |
| 614 | tm->slot = src_slot; |
| 615 | tm->move.dst_slot = dst_slot; |
| 616 | tm->move.nr_items = nr_items; |
| 617 | tm->op = MOD_LOG_MOVE_KEYS; |
| 618 | |
| 619 | ret = __tree_mod_log_insert(fs_info, tm); |
| 620 | out: |
| 621 | tree_mod_log_write_unlock(fs_info); |
| 622 | return ret; |
| 623 | } |
| 624 | |
| 625 | static inline void |
| 626 | __tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb) |
| 627 | { |
| 628 | int i; |
| 629 | u32 nritems; |
| 630 | int ret; |
| 631 | |
| 632 | if (btrfs_header_level(eb) == 0) |
| 633 | return; |
| 634 | |
| 635 | nritems = btrfs_header_nritems(eb); |
| 636 | for (i = nritems - 1; i >= 0; i--) { |
| 637 | ret = tree_mod_log_insert_key_locked(fs_info, eb, i, |
| 638 | MOD_LOG_KEY_REMOVE_WHILE_FREEING); |
| 639 | BUG_ON(ret < 0); |
| 640 | } |
| 641 | } |
| 642 | |
| 643 | static noinline int |
| 644 | tree_mod_log_insert_root(struct btrfs_fs_info *fs_info, |
| 645 | struct extent_buffer *old_root, |
| 646 | struct extent_buffer *new_root, gfp_t flags, |
| 647 | int log_removal) |
| 648 | { |
| 649 | struct tree_mod_elem *tm; |
| 650 | int ret; |
| 651 | |
| 652 | if (tree_mod_dont_log(fs_info, NULL)) |
| 653 | return 0; |
| 654 | |
| 655 | if (log_removal) |
| 656 | __tree_mod_log_free_eb(fs_info, old_root); |
| 657 | |
| 658 | ret = tree_mod_alloc(fs_info, flags, &tm); |
| 659 | if (ret < 0) |
| 660 | goto out; |
| 661 | |
| 662 | tm->index = new_root->start >> PAGE_CACHE_SHIFT; |
| 663 | tm->old_root.logical = old_root->start; |
| 664 | tm->old_root.level = btrfs_header_level(old_root); |
| 665 | tm->generation = btrfs_header_generation(old_root); |
| 666 | tm->op = MOD_LOG_ROOT_REPLACE; |
| 667 | |
| 668 | ret = __tree_mod_log_insert(fs_info, tm); |
| 669 | out: |
| 670 | tree_mod_log_write_unlock(fs_info); |
| 671 | return ret; |
| 672 | } |
| 673 | |
| 674 | static struct tree_mod_elem * |
| 675 | __tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq, |
| 676 | int smallest) |
| 677 | { |
| 678 | struct rb_root *tm_root; |
| 679 | struct rb_node *node; |
| 680 | struct tree_mod_elem *cur = NULL; |
| 681 | struct tree_mod_elem *found = NULL; |
| 682 | u64 index = start >> PAGE_CACHE_SHIFT; |
| 683 | |
| 684 | tree_mod_log_read_lock(fs_info); |
| 685 | tm_root = &fs_info->tree_mod_log; |
| 686 | node = tm_root->rb_node; |
| 687 | while (node) { |
| 688 | cur = container_of(node, struct tree_mod_elem, node); |
| 689 | if (cur->index < index) { |
| 690 | node = node->rb_left; |
| 691 | } else if (cur->index > index) { |
| 692 | node = node->rb_right; |
| 693 | } else if (cur->seq < min_seq) { |
| 694 | node = node->rb_left; |
| 695 | } else if (!smallest) { |
| 696 | /* we want the node with the highest seq */ |
| 697 | if (found) |
| 698 | BUG_ON(found->seq > cur->seq); |
| 699 | found = cur; |
| 700 | node = node->rb_left; |
| 701 | } else if (cur->seq > min_seq) { |
| 702 | /* we want the node with the smallest seq */ |
| 703 | if (found) |
| 704 | BUG_ON(found->seq < cur->seq); |
| 705 | found = cur; |
| 706 | node = node->rb_right; |
| 707 | } else { |
| 708 | found = cur; |
| 709 | break; |
| 710 | } |
| 711 | } |
| 712 | tree_mod_log_read_unlock(fs_info); |
| 713 | |
| 714 | return found; |
| 715 | } |
| 716 | |
| 717 | /* |
| 718 | * this returns the element from the log with the smallest time sequence |
| 719 | * value that's in the log (the oldest log item). any element with a time |
| 720 | * sequence lower than min_seq will be ignored. |
| 721 | */ |
| 722 | static struct tree_mod_elem * |
| 723 | tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start, |
| 724 | u64 min_seq) |
| 725 | { |
| 726 | return __tree_mod_log_search(fs_info, start, min_seq, 1); |
| 727 | } |
| 728 | |
| 729 | /* |
| 730 | * this returns the element from the log with the largest time sequence |
| 731 | * value that's in the log (the most recent log item). any element with |
| 732 | * a time sequence lower than min_seq will be ignored. |
| 733 | */ |
| 734 | static struct tree_mod_elem * |
| 735 | tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq) |
| 736 | { |
| 737 | return __tree_mod_log_search(fs_info, start, min_seq, 0); |
| 738 | } |
| 739 | |
| 740 | static noinline void |
| 741 | tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, |
| 742 | struct extent_buffer *src, unsigned long dst_offset, |
| 743 | unsigned long src_offset, int nr_items) |
| 744 | { |
| 745 | int ret; |
| 746 | int i; |
| 747 | |
| 748 | if (tree_mod_dont_log(fs_info, NULL)) |
| 749 | return; |
| 750 | |
| 751 | if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0) { |
| 752 | tree_mod_log_write_unlock(fs_info); |
| 753 | return; |
| 754 | } |
| 755 | |
| 756 | for (i = 0; i < nr_items; i++) { |
| 757 | ret = tree_mod_log_insert_key_locked(fs_info, src, |
| 758 | i + src_offset, |
| 759 | MOD_LOG_KEY_REMOVE); |
| 760 | BUG_ON(ret < 0); |
| 761 | ret = tree_mod_log_insert_key_locked(fs_info, dst, |
| 762 | i + dst_offset, |
| 763 | MOD_LOG_KEY_ADD); |
| 764 | BUG_ON(ret < 0); |
| 765 | } |
| 766 | |
| 767 | tree_mod_log_write_unlock(fs_info); |
| 768 | } |
| 769 | |
| 770 | static inline void |
| 771 | tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, |
| 772 | int dst_offset, int src_offset, int nr_items) |
| 773 | { |
| 774 | int ret; |
| 775 | ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset, |
| 776 | nr_items, GFP_NOFS); |
| 777 | BUG_ON(ret < 0); |
| 778 | } |
| 779 | |
| 780 | static noinline void |
| 781 | tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info, |
| 782 | struct extent_buffer *eb, int slot, int atomic) |
| 783 | { |
| 784 | int ret; |
| 785 | |
| 786 | ret = tree_mod_log_insert_key_mask(fs_info, eb, slot, |
| 787 | MOD_LOG_KEY_REPLACE, |
| 788 | atomic ? GFP_ATOMIC : GFP_NOFS); |
| 789 | BUG_ON(ret < 0); |
| 790 | } |
| 791 | |
| 792 | static noinline void |
| 793 | tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb) |
| 794 | { |
| 795 | if (tree_mod_dont_log(fs_info, eb)) |
| 796 | return; |
| 797 | |
| 798 | __tree_mod_log_free_eb(fs_info, eb); |
| 799 | |
| 800 | tree_mod_log_write_unlock(fs_info); |
| 801 | } |
| 802 | |
| 803 | static noinline void |
| 804 | tree_mod_log_set_root_pointer(struct btrfs_root *root, |
| 805 | struct extent_buffer *new_root_node, |
| 806 | int log_removal) |
| 807 | { |
| 808 | int ret; |
| 809 | ret = tree_mod_log_insert_root(root->fs_info, root->node, |
| 810 | new_root_node, GFP_NOFS, log_removal); |
| 811 | BUG_ON(ret < 0); |
| 812 | } |
| 813 | |
| 814 | /* |
| 815 | * check if the tree block can be shared by multiple trees |
| 816 | */ |
| 817 | int btrfs_block_can_be_shared(struct btrfs_root *root, |
| 818 | struct extent_buffer *buf) |
| 819 | { |
| 820 | /* |
| 821 | * Tree blocks not in refernece counted trees and tree roots |
| 822 | * are never shared. If a block was allocated after the last |
| 823 | * snapshot and the block was not allocated by tree relocation, |
| 824 | * we know the block is not shared. |
| 825 | */ |
| 826 | if (root->ref_cows && |
| 827 | buf != root->node && buf != root->commit_root && |
| 828 | (btrfs_header_generation(buf) <= |
| 829 | btrfs_root_last_snapshot(&root->root_item) || |
| 830 | btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) |
| 831 | return 1; |
| 832 | #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 |
| 833 | if (root->ref_cows && |
| 834 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| 835 | return 1; |
| 836 | #endif |
| 837 | return 0; |
| 838 | } |
| 839 | |
| 840 | static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, |
| 841 | struct btrfs_root *root, |
| 842 | struct extent_buffer *buf, |
| 843 | struct extent_buffer *cow, |
| 844 | int *last_ref) |
| 845 | { |
| 846 | u64 refs; |
| 847 | u64 owner; |
| 848 | u64 flags; |
| 849 | u64 new_flags = 0; |
| 850 | int ret; |
| 851 | |
| 852 | /* |
| 853 | * Backrefs update rules: |
| 854 | * |
| 855 | * Always use full backrefs for extent pointers in tree block |
| 856 | * allocated by tree relocation. |
| 857 | * |
| 858 | * If a shared tree block is no longer referenced by its owner |
| 859 | * tree (btrfs_header_owner(buf) == root->root_key.objectid), |
| 860 | * use full backrefs for extent pointers in tree block. |
| 861 | * |
| 862 | * If a tree block is been relocating |
| 863 | * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID), |
| 864 | * use full backrefs for extent pointers in tree block. |
| 865 | * The reason for this is some operations (such as drop tree) |
| 866 | * are only allowed for blocks use full backrefs. |
| 867 | */ |
| 868 | |
| 869 | if (btrfs_block_can_be_shared(root, buf)) { |
| 870 | ret = btrfs_lookup_extent_info(trans, root, buf->start, |
| 871 | btrfs_header_level(buf), 1, |
| 872 | &refs, &flags); |
| 873 | if (ret) |
| 874 | return ret; |
| 875 | if (refs == 0) { |
| 876 | ret = -EROFS; |
| 877 | btrfs_std_error(root->fs_info, ret); |
| 878 | return ret; |
| 879 | } |
| 880 | } else { |
| 881 | refs = 1; |
| 882 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
| 883 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| 884 | flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; |
| 885 | else |
| 886 | flags = 0; |
| 887 | } |
| 888 | |
| 889 | owner = btrfs_header_owner(buf); |
| 890 | BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID && |
| 891 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); |
| 892 | |
| 893 | if (refs > 1) { |
| 894 | if ((owner == root->root_key.objectid || |
| 895 | root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && |
| 896 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { |
| 897 | ret = btrfs_inc_ref(trans, root, buf, 1, 1); |
| 898 | BUG_ON(ret); /* -ENOMEM */ |
| 899 | |
| 900 | if (root->root_key.objectid == |
| 901 | BTRFS_TREE_RELOC_OBJECTID) { |
| 902 | ret = btrfs_dec_ref(trans, root, buf, 0, 1); |
| 903 | BUG_ON(ret); /* -ENOMEM */ |
| 904 | ret = btrfs_inc_ref(trans, root, cow, 1, 1); |
| 905 | BUG_ON(ret); /* -ENOMEM */ |
| 906 | } |
| 907 | new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; |
| 908 | } else { |
| 909 | |
| 910 | if (root->root_key.objectid == |
| 911 | BTRFS_TREE_RELOC_OBJECTID) |
| 912 | ret = btrfs_inc_ref(trans, root, cow, 1, 1); |
| 913 | else |
| 914 | ret = btrfs_inc_ref(trans, root, cow, 0, 1); |
| 915 | BUG_ON(ret); /* -ENOMEM */ |
| 916 | } |
| 917 | if (new_flags != 0) { |
| 918 | ret = btrfs_set_disk_extent_flags(trans, root, |
| 919 | buf->start, |
| 920 | buf->len, |
| 921 | new_flags, 0); |
| 922 | if (ret) |
| 923 | return ret; |
| 924 | } |
| 925 | } else { |
| 926 | if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) { |
| 927 | if (root->root_key.objectid == |
| 928 | BTRFS_TREE_RELOC_OBJECTID) |
| 929 | ret = btrfs_inc_ref(trans, root, cow, 1, 1); |
| 930 | else |
| 931 | ret = btrfs_inc_ref(trans, root, cow, 0, 1); |
| 932 | BUG_ON(ret); /* -ENOMEM */ |
| 933 | ret = btrfs_dec_ref(trans, root, buf, 1, 1); |
| 934 | BUG_ON(ret); /* -ENOMEM */ |
| 935 | } |
| 936 | clean_tree_block(trans, root, buf); |
| 937 | *last_ref = 1; |
| 938 | } |
| 939 | return 0; |
| 940 | } |
| 941 | |
| 942 | /* |
| 943 | * does the dirty work in cow of a single block. The parent block (if |
| 944 | * supplied) is updated to point to the new cow copy. The new buffer is marked |
| 945 | * dirty and returned locked. If you modify the block it needs to be marked |
| 946 | * dirty again. |
| 947 | * |
| 948 | * search_start -- an allocation hint for the new block |
| 949 | * |
| 950 | * empty_size -- a hint that you plan on doing more cow. This is the size in |
| 951 | * bytes the allocator should try to find free next to the block it returns. |
| 952 | * This is just a hint and may be ignored by the allocator. |
| 953 | */ |
| 954 | static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, |
| 955 | struct btrfs_root *root, |
| 956 | struct extent_buffer *buf, |
| 957 | struct extent_buffer *parent, int parent_slot, |
| 958 | struct extent_buffer **cow_ret, |
| 959 | u64 search_start, u64 empty_size) |
| 960 | { |
| 961 | struct btrfs_disk_key disk_key; |
| 962 | struct extent_buffer *cow; |
| 963 | int level, ret; |
| 964 | int last_ref = 0; |
| 965 | int unlock_orig = 0; |
| 966 | u64 parent_start; |
| 967 | |
| 968 | if (*cow_ret == buf) |
| 969 | unlock_orig = 1; |
| 970 | |
| 971 | btrfs_assert_tree_locked(buf); |
| 972 | |
| 973 | WARN_ON(root->ref_cows && trans->transid != |
| 974 | root->fs_info->running_transaction->transid); |
| 975 | WARN_ON(root->ref_cows && trans->transid != root->last_trans); |
| 976 | |
| 977 | level = btrfs_header_level(buf); |
| 978 | |
| 979 | if (level == 0) |
| 980 | btrfs_item_key(buf, &disk_key, 0); |
| 981 | else |
| 982 | btrfs_node_key(buf, &disk_key, 0); |
| 983 | |
| 984 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { |
| 985 | if (parent) |
| 986 | parent_start = parent->start; |
| 987 | else |
| 988 | parent_start = 0; |
| 989 | } else |
| 990 | parent_start = 0; |
| 991 | |
| 992 | cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start, |
| 993 | root->root_key.objectid, &disk_key, |
| 994 | level, search_start, empty_size); |
| 995 | if (IS_ERR(cow)) |
| 996 | return PTR_ERR(cow); |
| 997 | |
| 998 | /* cow is set to blocking by btrfs_init_new_buffer */ |
| 999 | |
| 1000 | copy_extent_buffer(cow, buf, 0, 0, cow->len); |
| 1001 | btrfs_set_header_bytenr(cow, cow->start); |
| 1002 | btrfs_set_header_generation(cow, trans->transid); |
| 1003 | btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
| 1004 | btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
| 1005 | BTRFS_HEADER_FLAG_RELOC); |
| 1006 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
| 1007 | btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
| 1008 | else |
| 1009 | btrfs_set_header_owner(cow, root->root_key.objectid); |
| 1010 | |
| 1011 | write_extent_buffer(cow, root->fs_info->fsid, |
| 1012 | (unsigned long)btrfs_header_fsid(cow), |
| 1013 | BTRFS_FSID_SIZE); |
| 1014 | |
| 1015 | ret = update_ref_for_cow(trans, root, buf, cow, &last_ref); |
| 1016 | if (ret) { |
| 1017 | btrfs_abort_transaction(trans, root, ret); |
| 1018 | return ret; |
| 1019 | } |
| 1020 | |
| 1021 | if (root->ref_cows) |
| 1022 | btrfs_reloc_cow_block(trans, root, buf, cow); |
| 1023 | |
| 1024 | if (buf == root->node) { |
| 1025 | WARN_ON(parent && parent != buf); |
| 1026 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
| 1027 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| 1028 | parent_start = buf->start; |
| 1029 | else |
| 1030 | parent_start = 0; |
| 1031 | |
| 1032 | extent_buffer_get(cow); |
| 1033 | tree_mod_log_set_root_pointer(root, cow, 1); |
| 1034 | rcu_assign_pointer(root->node, cow); |
| 1035 | |
| 1036 | btrfs_free_tree_block(trans, root, buf, parent_start, |
| 1037 | last_ref); |
| 1038 | free_extent_buffer(buf); |
| 1039 | add_root_to_dirty_list(root); |
| 1040 | } else { |
| 1041 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
| 1042 | parent_start = parent->start; |
| 1043 | else |
| 1044 | parent_start = 0; |
| 1045 | |
| 1046 | WARN_ON(trans->transid != btrfs_header_generation(parent)); |
| 1047 | tree_mod_log_insert_key(root->fs_info, parent, parent_slot, |
| 1048 | MOD_LOG_KEY_REPLACE); |
| 1049 | btrfs_set_node_blockptr(parent, parent_slot, |
| 1050 | cow->start); |
| 1051 | btrfs_set_node_ptr_generation(parent, parent_slot, |
| 1052 | trans->transid); |
| 1053 | btrfs_mark_buffer_dirty(parent); |
| 1054 | tree_mod_log_free_eb(root->fs_info, buf); |
| 1055 | btrfs_free_tree_block(trans, root, buf, parent_start, |
| 1056 | last_ref); |
| 1057 | } |
| 1058 | if (unlock_orig) |
| 1059 | btrfs_tree_unlock(buf); |
| 1060 | free_extent_buffer_stale(buf); |
| 1061 | btrfs_mark_buffer_dirty(cow); |
| 1062 | *cow_ret = cow; |
| 1063 | return 0; |
| 1064 | } |
| 1065 | |
| 1066 | /* |
| 1067 | * returns the logical address of the oldest predecessor of the given root. |
| 1068 | * entries older than time_seq are ignored. |
| 1069 | */ |
| 1070 | static struct tree_mod_elem * |
| 1071 | __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info, |
| 1072 | struct extent_buffer *eb_root, u64 time_seq) |
| 1073 | { |
| 1074 | struct tree_mod_elem *tm; |
| 1075 | struct tree_mod_elem *found = NULL; |
| 1076 | u64 root_logical = eb_root->start; |
| 1077 | int looped = 0; |
| 1078 | |
| 1079 | if (!time_seq) |
| 1080 | return 0; |
| 1081 | |
| 1082 | /* |
| 1083 | * the very last operation that's logged for a root is the replacement |
| 1084 | * operation (if it is replaced at all). this has the index of the *new* |
| 1085 | * root, making it the very first operation that's logged for this root. |
| 1086 | */ |
| 1087 | while (1) { |
| 1088 | tm = tree_mod_log_search_oldest(fs_info, root_logical, |
| 1089 | time_seq); |
| 1090 | if (!looped && !tm) |
| 1091 | return 0; |
| 1092 | /* |
| 1093 | * if there are no tree operation for the oldest root, we simply |
| 1094 | * return it. this should only happen if that (old) root is at |
| 1095 | * level 0. |
| 1096 | */ |
| 1097 | if (!tm) |
| 1098 | break; |
| 1099 | |
| 1100 | /* |
| 1101 | * if there's an operation that's not a root replacement, we |
| 1102 | * found the oldest version of our root. normally, we'll find a |
| 1103 | * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here. |
| 1104 | */ |
| 1105 | if (tm->op != MOD_LOG_ROOT_REPLACE) |
| 1106 | break; |
| 1107 | |
| 1108 | found = tm; |
| 1109 | root_logical = tm->old_root.logical; |
| 1110 | looped = 1; |
| 1111 | } |
| 1112 | |
| 1113 | /* if there's no old root to return, return what we found instead */ |
| 1114 | if (!found) |
| 1115 | found = tm; |
| 1116 | |
| 1117 | return found; |
| 1118 | } |
| 1119 | |
| 1120 | /* |
| 1121 | * tm is a pointer to the first operation to rewind within eb. then, all |
| 1122 | * previous operations will be rewinded (until we reach something older than |
| 1123 | * time_seq). |
| 1124 | */ |
| 1125 | static void |
| 1126 | __tree_mod_log_rewind(struct extent_buffer *eb, u64 time_seq, |
| 1127 | struct tree_mod_elem *first_tm) |
| 1128 | { |
| 1129 | u32 n; |
| 1130 | struct rb_node *next; |
| 1131 | struct tree_mod_elem *tm = first_tm; |
| 1132 | unsigned long o_dst; |
| 1133 | unsigned long o_src; |
| 1134 | unsigned long p_size = sizeof(struct btrfs_key_ptr); |
| 1135 | |
| 1136 | n = btrfs_header_nritems(eb); |
| 1137 | while (tm && tm->seq >= time_seq) { |
| 1138 | /* |
| 1139 | * all the operations are recorded with the operator used for |
| 1140 | * the modification. as we're going backwards, we do the |
| 1141 | * opposite of each operation here. |
| 1142 | */ |
| 1143 | switch (tm->op) { |
| 1144 | case MOD_LOG_KEY_REMOVE_WHILE_FREEING: |
| 1145 | BUG_ON(tm->slot < n); |
| 1146 | /* Fallthrough */ |
| 1147 | case MOD_LOG_KEY_REMOVE_WHILE_MOVING: |
| 1148 | case MOD_LOG_KEY_REMOVE: |
| 1149 | btrfs_set_node_key(eb, &tm->key, tm->slot); |
| 1150 | btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); |
| 1151 | btrfs_set_node_ptr_generation(eb, tm->slot, |
| 1152 | tm->generation); |
| 1153 | n++; |
| 1154 | break; |
| 1155 | case MOD_LOG_KEY_REPLACE: |
| 1156 | BUG_ON(tm->slot >= n); |
| 1157 | btrfs_set_node_key(eb, &tm->key, tm->slot); |
| 1158 | btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); |
| 1159 | btrfs_set_node_ptr_generation(eb, tm->slot, |
| 1160 | tm->generation); |
| 1161 | break; |
| 1162 | case MOD_LOG_KEY_ADD: |
| 1163 | /* if a move operation is needed it's in the log */ |
| 1164 | n--; |
| 1165 | break; |
| 1166 | case MOD_LOG_MOVE_KEYS: |
| 1167 | o_dst = btrfs_node_key_ptr_offset(tm->slot); |
| 1168 | o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot); |
| 1169 | memmove_extent_buffer(eb, o_dst, o_src, |
| 1170 | tm->move.nr_items * p_size); |
| 1171 | break; |
| 1172 | case MOD_LOG_ROOT_REPLACE: |
| 1173 | /* |
| 1174 | * this operation is special. for roots, this must be |
| 1175 | * handled explicitly before rewinding. |
| 1176 | * for non-roots, this operation may exist if the node |
| 1177 | * was a root: root A -> child B; then A gets empty and |
| 1178 | * B is promoted to the new root. in the mod log, we'll |
| 1179 | * have a root-replace operation for B, a tree block |
| 1180 | * that is no root. we simply ignore that operation. |
| 1181 | */ |
| 1182 | break; |
| 1183 | } |
| 1184 | next = rb_next(&tm->node); |
| 1185 | if (!next) |
| 1186 | break; |
| 1187 | tm = container_of(next, struct tree_mod_elem, node); |
| 1188 | if (tm->index != first_tm->index) |
| 1189 | break; |
| 1190 | } |
| 1191 | btrfs_set_header_nritems(eb, n); |
| 1192 | } |
| 1193 | |
| 1194 | /* |
| 1195 | * Called with eb read locked. If the buffer cannot be rewinded, the same buffer |
| 1196 | * is returned. If rewind operations happen, a fresh buffer is returned. The |
| 1197 | * returned buffer is always read-locked. If the returned buffer is not the |
| 1198 | * input buffer, the lock on the input buffer is released and the input buffer |
| 1199 | * is freed (its refcount is decremented). |
| 1200 | */ |
| 1201 | static struct extent_buffer * |
| 1202 | tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, |
| 1203 | u64 time_seq) |
| 1204 | { |
| 1205 | struct extent_buffer *eb_rewin; |
| 1206 | struct tree_mod_elem *tm; |
| 1207 | |
| 1208 | if (!time_seq) |
| 1209 | return eb; |
| 1210 | |
| 1211 | if (btrfs_header_level(eb) == 0) |
| 1212 | return eb; |
| 1213 | |
| 1214 | tm = tree_mod_log_search(fs_info, eb->start, time_seq); |
| 1215 | if (!tm) |
| 1216 | return eb; |
| 1217 | |
| 1218 | if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) { |
| 1219 | BUG_ON(tm->slot != 0); |
| 1220 | eb_rewin = alloc_dummy_extent_buffer(eb->start, |
| 1221 | fs_info->tree_root->nodesize); |
| 1222 | BUG_ON(!eb_rewin); |
| 1223 | btrfs_set_header_bytenr(eb_rewin, eb->start); |
| 1224 | btrfs_set_header_backref_rev(eb_rewin, |
| 1225 | btrfs_header_backref_rev(eb)); |
| 1226 | btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb)); |
| 1227 | btrfs_set_header_level(eb_rewin, btrfs_header_level(eb)); |
| 1228 | } else { |
| 1229 | eb_rewin = btrfs_clone_extent_buffer(eb); |
| 1230 | BUG_ON(!eb_rewin); |
| 1231 | } |
| 1232 | |
| 1233 | extent_buffer_get(eb_rewin); |
| 1234 | btrfs_tree_read_unlock(eb); |
| 1235 | free_extent_buffer(eb); |
| 1236 | |
| 1237 | extent_buffer_get(eb_rewin); |
| 1238 | btrfs_tree_read_lock(eb_rewin); |
| 1239 | __tree_mod_log_rewind(eb_rewin, time_seq, tm); |
| 1240 | WARN_ON(btrfs_header_nritems(eb_rewin) > |
| 1241 | BTRFS_NODEPTRS_PER_BLOCK(fs_info->tree_root)); |
| 1242 | |
| 1243 | return eb_rewin; |
| 1244 | } |
| 1245 | |
| 1246 | /* |
| 1247 | * get_old_root() rewinds the state of @root's root node to the given @time_seq |
| 1248 | * value. If there are no changes, the current root->root_node is returned. If |
| 1249 | * anything changed in between, there's a fresh buffer allocated on which the |
| 1250 | * rewind operations are done. In any case, the returned buffer is read locked. |
| 1251 | * Returns NULL on error (with no locks held). |
| 1252 | */ |
| 1253 | static inline struct extent_buffer * |
| 1254 | get_old_root(struct btrfs_root *root, u64 time_seq) |
| 1255 | { |
| 1256 | struct tree_mod_elem *tm; |
| 1257 | struct extent_buffer *eb = NULL; |
| 1258 | struct extent_buffer *eb_root; |
| 1259 | struct extent_buffer *old; |
| 1260 | struct tree_mod_root *old_root = NULL; |
| 1261 | u64 old_generation = 0; |
| 1262 | u64 logical; |
| 1263 | u32 blocksize; |
| 1264 | |
| 1265 | eb_root = btrfs_read_lock_root_node(root); |
| 1266 | tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq); |
| 1267 | if (!tm) |
| 1268 | return eb_root; |
| 1269 | |
| 1270 | if (tm->op == MOD_LOG_ROOT_REPLACE) { |
| 1271 | old_root = &tm->old_root; |
| 1272 | old_generation = tm->generation; |
| 1273 | logical = old_root->logical; |
| 1274 | } else { |
| 1275 | logical = eb_root->start; |
| 1276 | } |
| 1277 | |
| 1278 | tm = tree_mod_log_search(root->fs_info, logical, time_seq); |
| 1279 | if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) { |
| 1280 | btrfs_tree_read_unlock(eb_root); |
| 1281 | free_extent_buffer(eb_root); |
| 1282 | blocksize = btrfs_level_size(root, old_root->level); |
| 1283 | old = read_tree_block(root, logical, blocksize, 0); |
| 1284 | if (!old) { |
| 1285 | pr_warn("btrfs: failed to read tree block %llu from get_old_root\n", |
| 1286 | logical); |
| 1287 | WARN_ON(1); |
| 1288 | } else { |
| 1289 | eb = btrfs_clone_extent_buffer(old); |
| 1290 | free_extent_buffer(old); |
| 1291 | } |
| 1292 | } else if (old_root) { |
| 1293 | btrfs_tree_read_unlock(eb_root); |
| 1294 | free_extent_buffer(eb_root); |
| 1295 | eb = alloc_dummy_extent_buffer(logical, root->nodesize); |
| 1296 | } else { |
| 1297 | eb = btrfs_clone_extent_buffer(eb_root); |
| 1298 | btrfs_tree_read_unlock(eb_root); |
| 1299 | free_extent_buffer(eb_root); |
| 1300 | } |
| 1301 | |
| 1302 | if (!eb) |
| 1303 | return NULL; |
| 1304 | extent_buffer_get(eb); |
| 1305 | btrfs_tree_read_lock(eb); |
| 1306 | if (old_root) { |
| 1307 | btrfs_set_header_bytenr(eb, eb->start); |
| 1308 | btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV); |
| 1309 | btrfs_set_header_owner(eb, btrfs_header_owner(eb_root)); |
| 1310 | btrfs_set_header_level(eb, old_root->level); |
| 1311 | btrfs_set_header_generation(eb, old_generation); |
| 1312 | } |
| 1313 | if (tm) |
| 1314 | __tree_mod_log_rewind(eb, time_seq, tm); |
| 1315 | else |
| 1316 | WARN_ON(btrfs_header_level(eb) != 0); |
| 1317 | WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(root)); |
| 1318 | |
| 1319 | return eb; |
| 1320 | } |
| 1321 | |
| 1322 | int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq) |
| 1323 | { |
| 1324 | struct tree_mod_elem *tm; |
| 1325 | int level; |
| 1326 | struct extent_buffer *eb_root = btrfs_root_node(root); |
| 1327 | |
| 1328 | tm = __tree_mod_log_oldest_root(root->fs_info, eb_root, time_seq); |
| 1329 | if (tm && tm->op == MOD_LOG_ROOT_REPLACE) { |
| 1330 | level = tm->old_root.level; |
| 1331 | } else { |
| 1332 | level = btrfs_header_level(eb_root); |
| 1333 | } |
| 1334 | free_extent_buffer(eb_root); |
| 1335 | |
| 1336 | return level; |
| 1337 | } |
| 1338 | |
| 1339 | static inline int should_cow_block(struct btrfs_trans_handle *trans, |
| 1340 | struct btrfs_root *root, |
| 1341 | struct extent_buffer *buf) |
| 1342 | { |
| 1343 | /* ensure we can see the force_cow */ |
| 1344 | smp_rmb(); |
| 1345 | |
| 1346 | /* |
| 1347 | * We do not need to cow a block if |
| 1348 | * 1) this block is not created or changed in this transaction; |
| 1349 | * 2) this block does not belong to TREE_RELOC tree; |
| 1350 | * 3) the root is not forced COW. |
| 1351 | * |
| 1352 | * What is forced COW: |
| 1353 | * when we create snapshot during commiting the transaction, |
| 1354 | * after we've finished coping src root, we must COW the shared |
| 1355 | * block to ensure the metadata consistency. |
| 1356 | */ |
| 1357 | if (btrfs_header_generation(buf) == trans->transid && |
| 1358 | !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) && |
| 1359 | !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && |
| 1360 | btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) && |
| 1361 | !root->force_cow) |
| 1362 | return 0; |
| 1363 | return 1; |
| 1364 | } |
| 1365 | |
| 1366 | /* |
| 1367 | * cows a single block, see __btrfs_cow_block for the real work. |
| 1368 | * This version of it has extra checks so that a block isn't cow'd more than |
| 1369 | * once per transaction, as long as it hasn't been written yet |
| 1370 | */ |
| 1371 | noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, |
| 1372 | struct btrfs_root *root, struct extent_buffer *buf, |
| 1373 | struct extent_buffer *parent, int parent_slot, |
| 1374 | struct extent_buffer **cow_ret) |
| 1375 | { |
| 1376 | u64 search_start; |
| 1377 | int ret; |
| 1378 | |
| 1379 | if (trans->transaction != root->fs_info->running_transaction) |
| 1380 | WARN(1, KERN_CRIT "trans %llu running %llu\n", |
| 1381 | (unsigned long long)trans->transid, |
| 1382 | (unsigned long long) |
| 1383 | root->fs_info->running_transaction->transid); |
| 1384 | |
| 1385 | if (trans->transid != root->fs_info->generation) |
| 1386 | WARN(1, KERN_CRIT "trans %llu running %llu\n", |
| 1387 | (unsigned long long)trans->transid, |
| 1388 | (unsigned long long)root->fs_info->generation); |
| 1389 | |
| 1390 | if (!should_cow_block(trans, root, buf)) { |
| 1391 | *cow_ret = buf; |
| 1392 | return 0; |
| 1393 | } |
| 1394 | |
| 1395 | search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1); |
| 1396 | |
| 1397 | if (parent) |
| 1398 | btrfs_set_lock_blocking(parent); |
| 1399 | btrfs_set_lock_blocking(buf); |
| 1400 | |
| 1401 | ret = __btrfs_cow_block(trans, root, buf, parent, |
| 1402 | parent_slot, cow_ret, search_start, 0); |
| 1403 | |
| 1404 | trace_btrfs_cow_block(root, buf, *cow_ret); |
| 1405 | |
| 1406 | return ret; |
| 1407 | } |
| 1408 | |
| 1409 | /* |
| 1410 | * helper function for defrag to decide if two blocks pointed to by a |
| 1411 | * node are actually close by |
| 1412 | */ |
| 1413 | static int close_blocks(u64 blocknr, u64 other, u32 blocksize) |
| 1414 | { |
| 1415 | if (blocknr < other && other - (blocknr + blocksize) < 32768) |
| 1416 | return 1; |
| 1417 | if (blocknr > other && blocknr - (other + blocksize) < 32768) |
| 1418 | return 1; |
| 1419 | return 0; |
| 1420 | } |
| 1421 | |
| 1422 | /* |
| 1423 | * compare two keys in a memcmp fashion |
| 1424 | */ |
| 1425 | static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2) |
| 1426 | { |
| 1427 | struct btrfs_key k1; |
| 1428 | |
| 1429 | btrfs_disk_key_to_cpu(&k1, disk); |
| 1430 | |
| 1431 | return btrfs_comp_cpu_keys(&k1, k2); |
| 1432 | } |
| 1433 | |
| 1434 | /* |
| 1435 | * same as comp_keys only with two btrfs_key's |
| 1436 | */ |
| 1437 | int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2) |
| 1438 | { |
| 1439 | if (k1->objectid > k2->objectid) |
| 1440 | return 1; |
| 1441 | if (k1->objectid < k2->objectid) |
| 1442 | return -1; |
| 1443 | if (k1->type > k2->type) |
| 1444 | return 1; |
| 1445 | if (k1->type < k2->type) |
| 1446 | return -1; |
| 1447 | if (k1->offset > k2->offset) |
| 1448 | return 1; |
| 1449 | if (k1->offset < k2->offset) |
| 1450 | return -1; |
| 1451 | return 0; |
| 1452 | } |
| 1453 | |
| 1454 | /* |
| 1455 | * this is used by the defrag code to go through all the |
| 1456 | * leaves pointed to by a node and reallocate them so that |
| 1457 | * disk order is close to key order |
| 1458 | */ |
| 1459 | int btrfs_realloc_node(struct btrfs_trans_handle *trans, |
| 1460 | struct btrfs_root *root, struct extent_buffer *parent, |
| 1461 | int start_slot, u64 *last_ret, |
| 1462 | struct btrfs_key *progress) |
| 1463 | { |
| 1464 | struct extent_buffer *cur; |
| 1465 | u64 blocknr; |
| 1466 | u64 gen; |
| 1467 | u64 search_start = *last_ret; |
| 1468 | u64 last_block = 0; |
| 1469 | u64 other; |
| 1470 | u32 parent_nritems; |
| 1471 | int end_slot; |
| 1472 | int i; |
| 1473 | int err = 0; |
| 1474 | int parent_level; |
| 1475 | int uptodate; |
| 1476 | u32 blocksize; |
| 1477 | int progress_passed = 0; |
| 1478 | struct btrfs_disk_key disk_key; |
| 1479 | |
| 1480 | parent_level = btrfs_header_level(parent); |
| 1481 | |
| 1482 | WARN_ON(trans->transaction != root->fs_info->running_transaction); |
| 1483 | WARN_ON(trans->transid != root->fs_info->generation); |
| 1484 | |
| 1485 | parent_nritems = btrfs_header_nritems(parent); |
| 1486 | blocksize = btrfs_level_size(root, parent_level - 1); |
| 1487 | end_slot = parent_nritems; |
| 1488 | |
| 1489 | if (parent_nritems == 1) |
| 1490 | return 0; |
| 1491 | |
| 1492 | btrfs_set_lock_blocking(parent); |
| 1493 | |
| 1494 | for (i = start_slot; i < end_slot; i++) { |
| 1495 | int close = 1; |
| 1496 | |
| 1497 | btrfs_node_key(parent, &disk_key, i); |
| 1498 | if (!progress_passed && comp_keys(&disk_key, progress) < 0) |
| 1499 | continue; |
| 1500 | |
| 1501 | progress_passed = 1; |
| 1502 | blocknr = btrfs_node_blockptr(parent, i); |
| 1503 | gen = btrfs_node_ptr_generation(parent, i); |
| 1504 | if (last_block == 0) |
| 1505 | last_block = blocknr; |
| 1506 | |
| 1507 | if (i > 0) { |
| 1508 | other = btrfs_node_blockptr(parent, i - 1); |
| 1509 | close = close_blocks(blocknr, other, blocksize); |
| 1510 | } |
| 1511 | if (!close && i < end_slot - 2) { |
| 1512 | other = btrfs_node_blockptr(parent, i + 1); |
| 1513 | close = close_blocks(blocknr, other, blocksize); |
| 1514 | } |
| 1515 | if (close) { |
| 1516 | last_block = blocknr; |
| 1517 | continue; |
| 1518 | } |
| 1519 | |
| 1520 | cur = btrfs_find_tree_block(root, blocknr, blocksize); |
| 1521 | if (cur) |
| 1522 | uptodate = btrfs_buffer_uptodate(cur, gen, 0); |
| 1523 | else |
| 1524 | uptodate = 0; |
| 1525 | if (!cur || !uptodate) { |
| 1526 | if (!cur) { |
| 1527 | cur = read_tree_block(root, blocknr, |
| 1528 | blocksize, gen); |
| 1529 | if (!cur) |
| 1530 | return -EIO; |
| 1531 | } else if (!uptodate) { |
| 1532 | err = btrfs_read_buffer(cur, gen); |
| 1533 | if (err) { |
| 1534 | free_extent_buffer(cur); |
| 1535 | return err; |
| 1536 | } |
| 1537 | } |
| 1538 | } |
| 1539 | if (search_start == 0) |
| 1540 | search_start = last_block; |
| 1541 | |
| 1542 | btrfs_tree_lock(cur); |
| 1543 | btrfs_set_lock_blocking(cur); |
| 1544 | err = __btrfs_cow_block(trans, root, cur, parent, i, |
| 1545 | &cur, search_start, |
| 1546 | min(16 * blocksize, |
| 1547 | (end_slot - i) * blocksize)); |
| 1548 | if (err) { |
| 1549 | btrfs_tree_unlock(cur); |
| 1550 | free_extent_buffer(cur); |
| 1551 | break; |
| 1552 | } |
| 1553 | search_start = cur->start; |
| 1554 | last_block = cur->start; |
| 1555 | *last_ret = search_start; |
| 1556 | btrfs_tree_unlock(cur); |
| 1557 | free_extent_buffer(cur); |
| 1558 | } |
| 1559 | return err; |
| 1560 | } |
| 1561 | |
| 1562 | /* |
| 1563 | * The leaf data grows from end-to-front in the node. |
| 1564 | * this returns the address of the start of the last item, |
| 1565 | * which is the stop of the leaf data stack |
| 1566 | */ |
| 1567 | static inline unsigned int leaf_data_end(struct btrfs_root *root, |
| 1568 | struct extent_buffer *leaf) |
| 1569 | { |
| 1570 | u32 nr = btrfs_header_nritems(leaf); |
| 1571 | if (nr == 0) |
| 1572 | return BTRFS_LEAF_DATA_SIZE(root); |
| 1573 | return btrfs_item_offset_nr(leaf, nr - 1); |
| 1574 | } |
| 1575 | |
| 1576 | |
| 1577 | /* |
| 1578 | * search for key in the extent_buffer. The items start at offset p, |
| 1579 | * and they are item_size apart. There are 'max' items in p. |
| 1580 | * |
| 1581 | * the slot in the array is returned via slot, and it points to |
| 1582 | * the place where you would insert key if it is not found in |
| 1583 | * the array. |
| 1584 | * |
| 1585 | * slot may point to max if the key is bigger than all of the keys |
| 1586 | */ |
| 1587 | static noinline int generic_bin_search(struct extent_buffer *eb, |
| 1588 | unsigned long p, |
| 1589 | int item_size, struct btrfs_key *key, |
| 1590 | int max, int *slot) |
| 1591 | { |
| 1592 | int low = 0; |
| 1593 | int high = max; |
| 1594 | int mid; |
| 1595 | int ret; |
| 1596 | struct btrfs_disk_key *tmp = NULL; |
| 1597 | struct btrfs_disk_key unaligned; |
| 1598 | unsigned long offset; |
| 1599 | char *kaddr = NULL; |
| 1600 | unsigned long map_start = 0; |
| 1601 | unsigned long map_len = 0; |
| 1602 | int err; |
| 1603 | |
| 1604 | while (low < high) { |
| 1605 | mid = (low + high) / 2; |
| 1606 | offset = p + mid * item_size; |
| 1607 | |
| 1608 | if (!kaddr || offset < map_start || |
| 1609 | (offset + sizeof(struct btrfs_disk_key)) > |
| 1610 | map_start + map_len) { |
| 1611 | |
| 1612 | err = map_private_extent_buffer(eb, offset, |
| 1613 | sizeof(struct btrfs_disk_key), |
| 1614 | &kaddr, &map_start, &map_len); |
| 1615 | |
| 1616 | if (!err) { |
| 1617 | tmp = (struct btrfs_disk_key *)(kaddr + offset - |
| 1618 | map_start); |
| 1619 | } else { |
| 1620 | read_extent_buffer(eb, &unaligned, |
| 1621 | offset, sizeof(unaligned)); |
| 1622 | tmp = &unaligned; |
| 1623 | } |
| 1624 | |
| 1625 | } else { |
| 1626 | tmp = (struct btrfs_disk_key *)(kaddr + offset - |
| 1627 | map_start); |
| 1628 | } |
| 1629 | ret = comp_keys(tmp, key); |
| 1630 | |
| 1631 | if (ret < 0) |
| 1632 | low = mid + 1; |
| 1633 | else if (ret > 0) |
| 1634 | high = mid; |
| 1635 | else { |
| 1636 | *slot = mid; |
| 1637 | return 0; |
| 1638 | } |
| 1639 | } |
| 1640 | *slot = low; |
| 1641 | return 1; |
| 1642 | } |
| 1643 | |
| 1644 | /* |
| 1645 | * simple bin_search frontend that does the right thing for |
| 1646 | * leaves vs nodes |
| 1647 | */ |
| 1648 | static int bin_search(struct extent_buffer *eb, struct btrfs_key *key, |
| 1649 | int level, int *slot) |
| 1650 | { |
| 1651 | if (level == 0) |
| 1652 | return generic_bin_search(eb, |
| 1653 | offsetof(struct btrfs_leaf, items), |
| 1654 | sizeof(struct btrfs_item), |
| 1655 | key, btrfs_header_nritems(eb), |
| 1656 | slot); |
| 1657 | else |
| 1658 | return generic_bin_search(eb, |
| 1659 | offsetof(struct btrfs_node, ptrs), |
| 1660 | sizeof(struct btrfs_key_ptr), |
| 1661 | key, btrfs_header_nritems(eb), |
| 1662 | slot); |
| 1663 | } |
| 1664 | |
| 1665 | int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key, |
| 1666 | int level, int *slot) |
| 1667 | { |
| 1668 | return bin_search(eb, key, level, slot); |
| 1669 | } |
| 1670 | |
| 1671 | static void root_add_used(struct btrfs_root *root, u32 size) |
| 1672 | { |
| 1673 | spin_lock(&root->accounting_lock); |
| 1674 | btrfs_set_root_used(&root->root_item, |
| 1675 | btrfs_root_used(&root->root_item) + size); |
| 1676 | spin_unlock(&root->accounting_lock); |
| 1677 | } |
| 1678 | |
| 1679 | static void root_sub_used(struct btrfs_root *root, u32 size) |
| 1680 | { |
| 1681 | spin_lock(&root->accounting_lock); |
| 1682 | btrfs_set_root_used(&root->root_item, |
| 1683 | btrfs_root_used(&root->root_item) - size); |
| 1684 | spin_unlock(&root->accounting_lock); |
| 1685 | } |
| 1686 | |
| 1687 | /* given a node and slot number, this reads the blocks it points to. The |
| 1688 | * extent buffer is returned with a reference taken (but unlocked). |
| 1689 | * NULL is returned on error. |
| 1690 | */ |
| 1691 | static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root, |
| 1692 | struct extent_buffer *parent, int slot) |
| 1693 | { |
| 1694 | int level = btrfs_header_level(parent); |
| 1695 | if (slot < 0) |
| 1696 | return NULL; |
| 1697 | if (slot >= btrfs_header_nritems(parent)) |
| 1698 | return NULL; |
| 1699 | |
| 1700 | BUG_ON(level == 0); |
| 1701 | |
| 1702 | return read_tree_block(root, btrfs_node_blockptr(parent, slot), |
| 1703 | btrfs_level_size(root, level - 1), |
| 1704 | btrfs_node_ptr_generation(parent, slot)); |
| 1705 | } |
| 1706 | |
| 1707 | /* |
| 1708 | * node level balancing, used to make sure nodes are in proper order for |
| 1709 | * item deletion. We balance from the top down, so we have to make sure |
| 1710 | * that a deletion won't leave an node completely empty later on. |
| 1711 | */ |
| 1712 | static noinline int balance_level(struct btrfs_trans_handle *trans, |
| 1713 | struct btrfs_root *root, |
| 1714 | struct btrfs_path *path, int level) |
| 1715 | { |
| 1716 | struct extent_buffer *right = NULL; |
| 1717 | struct extent_buffer *mid; |
| 1718 | struct extent_buffer *left = NULL; |
| 1719 | struct extent_buffer *parent = NULL; |
| 1720 | int ret = 0; |
| 1721 | int wret; |
| 1722 | int pslot; |
| 1723 | int orig_slot = path->slots[level]; |
| 1724 | u64 orig_ptr; |
| 1725 | |
| 1726 | if (level == 0) |
| 1727 | return 0; |
| 1728 | |
| 1729 | mid = path->nodes[level]; |
| 1730 | |
| 1731 | WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK && |
| 1732 | path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING); |
| 1733 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
| 1734 | |
| 1735 | orig_ptr = btrfs_node_blockptr(mid, orig_slot); |
| 1736 | |
| 1737 | if (level < BTRFS_MAX_LEVEL - 1) { |
| 1738 | parent = path->nodes[level + 1]; |
| 1739 | pslot = path->slots[level + 1]; |
| 1740 | } |
| 1741 | |
| 1742 | /* |
| 1743 | * deal with the case where there is only one pointer in the root |
| 1744 | * by promoting the node below to a root |
| 1745 | */ |
| 1746 | if (!parent) { |
| 1747 | struct extent_buffer *child; |
| 1748 | |
| 1749 | if (btrfs_header_nritems(mid) != 1) |
| 1750 | return 0; |
| 1751 | |
| 1752 | /* promote the child to a root */ |
| 1753 | child = read_node_slot(root, mid, 0); |
| 1754 | if (!child) { |
| 1755 | ret = -EROFS; |
| 1756 | btrfs_std_error(root->fs_info, ret); |
| 1757 | goto enospc; |
| 1758 | } |
| 1759 | |
| 1760 | btrfs_tree_lock(child); |
| 1761 | btrfs_set_lock_blocking(child); |
| 1762 | ret = btrfs_cow_block(trans, root, child, mid, 0, &child); |
| 1763 | if (ret) { |
| 1764 | btrfs_tree_unlock(child); |
| 1765 | free_extent_buffer(child); |
| 1766 | goto enospc; |
| 1767 | } |
| 1768 | |
| 1769 | tree_mod_log_set_root_pointer(root, child, 1); |
| 1770 | rcu_assign_pointer(root->node, child); |
| 1771 | |
| 1772 | add_root_to_dirty_list(root); |
| 1773 | btrfs_tree_unlock(child); |
| 1774 | |
| 1775 | path->locks[level] = 0; |
| 1776 | path->nodes[level] = NULL; |
| 1777 | clean_tree_block(trans, root, mid); |
| 1778 | btrfs_tree_unlock(mid); |
| 1779 | /* once for the path */ |
| 1780 | free_extent_buffer(mid); |
| 1781 | |
| 1782 | root_sub_used(root, mid->len); |
| 1783 | btrfs_free_tree_block(trans, root, mid, 0, 1); |
| 1784 | /* once for the root ptr */ |
| 1785 | free_extent_buffer_stale(mid); |
| 1786 | return 0; |
| 1787 | } |
| 1788 | if (btrfs_header_nritems(mid) > |
| 1789 | BTRFS_NODEPTRS_PER_BLOCK(root) / 4) |
| 1790 | return 0; |
| 1791 | |
| 1792 | left = read_node_slot(root, parent, pslot - 1); |
| 1793 | if (left) { |
| 1794 | btrfs_tree_lock(left); |
| 1795 | btrfs_set_lock_blocking(left); |
| 1796 | wret = btrfs_cow_block(trans, root, left, |
| 1797 | parent, pslot - 1, &left); |
| 1798 | if (wret) { |
| 1799 | ret = wret; |
| 1800 | goto enospc; |
| 1801 | } |
| 1802 | } |
| 1803 | right = read_node_slot(root, parent, pslot + 1); |
| 1804 | if (right) { |
| 1805 | btrfs_tree_lock(right); |
| 1806 | btrfs_set_lock_blocking(right); |
| 1807 | wret = btrfs_cow_block(trans, root, right, |
| 1808 | parent, pslot + 1, &right); |
| 1809 | if (wret) { |
| 1810 | ret = wret; |
| 1811 | goto enospc; |
| 1812 | } |
| 1813 | } |
| 1814 | |
| 1815 | /* first, try to make some room in the middle buffer */ |
| 1816 | if (left) { |
| 1817 | orig_slot += btrfs_header_nritems(left); |
| 1818 | wret = push_node_left(trans, root, left, mid, 1); |
| 1819 | if (wret < 0) |
| 1820 | ret = wret; |
| 1821 | } |
| 1822 | |
| 1823 | /* |
| 1824 | * then try to empty the right most buffer into the middle |
| 1825 | */ |
| 1826 | if (right) { |
| 1827 | wret = push_node_left(trans, root, mid, right, 1); |
| 1828 | if (wret < 0 && wret != -ENOSPC) |
| 1829 | ret = wret; |
| 1830 | if (btrfs_header_nritems(right) == 0) { |
| 1831 | clean_tree_block(trans, root, right); |
| 1832 | btrfs_tree_unlock(right); |
| 1833 | del_ptr(trans, root, path, level + 1, pslot + 1); |
| 1834 | root_sub_used(root, right->len); |
| 1835 | btrfs_free_tree_block(trans, root, right, 0, 1); |
| 1836 | free_extent_buffer_stale(right); |
| 1837 | right = NULL; |
| 1838 | } else { |
| 1839 | struct btrfs_disk_key right_key; |
| 1840 | btrfs_node_key(right, &right_key, 0); |
| 1841 | tree_mod_log_set_node_key(root->fs_info, parent, |
| 1842 | pslot + 1, 0); |
| 1843 | btrfs_set_node_key(parent, &right_key, pslot + 1); |
| 1844 | btrfs_mark_buffer_dirty(parent); |
| 1845 | } |
| 1846 | } |
| 1847 | if (btrfs_header_nritems(mid) == 1) { |
| 1848 | /* |
| 1849 | * we're not allowed to leave a node with one item in the |
| 1850 | * tree during a delete. A deletion from lower in the tree |
| 1851 | * could try to delete the only pointer in this node. |
| 1852 | * So, pull some keys from the left. |
| 1853 | * There has to be a left pointer at this point because |
| 1854 | * otherwise we would have pulled some pointers from the |
| 1855 | * right |
| 1856 | */ |
| 1857 | if (!left) { |
| 1858 | ret = -EROFS; |
| 1859 | btrfs_std_error(root->fs_info, ret); |
| 1860 | goto enospc; |
| 1861 | } |
| 1862 | wret = balance_node_right(trans, root, mid, left); |
| 1863 | if (wret < 0) { |
| 1864 | ret = wret; |
| 1865 | goto enospc; |
| 1866 | } |
| 1867 | if (wret == 1) { |
| 1868 | wret = push_node_left(trans, root, left, mid, 1); |
| 1869 | if (wret < 0) |
| 1870 | ret = wret; |
| 1871 | } |
| 1872 | BUG_ON(wret == 1); |
| 1873 | } |
| 1874 | if (btrfs_header_nritems(mid) == 0) { |
| 1875 | clean_tree_block(trans, root, mid); |
| 1876 | btrfs_tree_unlock(mid); |
| 1877 | del_ptr(trans, root, path, level + 1, pslot); |
| 1878 | root_sub_used(root, mid->len); |
| 1879 | btrfs_free_tree_block(trans, root, mid, 0, 1); |
| 1880 | free_extent_buffer_stale(mid); |
| 1881 | mid = NULL; |
| 1882 | } else { |
| 1883 | /* update the parent key to reflect our changes */ |
| 1884 | struct btrfs_disk_key mid_key; |
| 1885 | btrfs_node_key(mid, &mid_key, 0); |
| 1886 | tree_mod_log_set_node_key(root->fs_info, parent, |
| 1887 | pslot, 0); |
| 1888 | btrfs_set_node_key(parent, &mid_key, pslot); |
| 1889 | btrfs_mark_buffer_dirty(parent); |
| 1890 | } |
| 1891 | |
| 1892 | /* update the path */ |
| 1893 | if (left) { |
| 1894 | if (btrfs_header_nritems(left) > orig_slot) { |
| 1895 | extent_buffer_get(left); |
| 1896 | /* left was locked after cow */ |
| 1897 | path->nodes[level] = left; |
| 1898 | path->slots[level + 1] -= 1; |
| 1899 | path->slots[level] = orig_slot; |
| 1900 | if (mid) { |
| 1901 | btrfs_tree_unlock(mid); |
| 1902 | free_extent_buffer(mid); |
| 1903 | } |
| 1904 | } else { |
| 1905 | orig_slot -= btrfs_header_nritems(left); |
| 1906 | path->slots[level] = orig_slot; |
| 1907 | } |
| 1908 | } |
| 1909 | /* double check we haven't messed things up */ |
| 1910 | if (orig_ptr != |
| 1911 | btrfs_node_blockptr(path->nodes[level], path->slots[level])) |
| 1912 | BUG(); |
| 1913 | enospc: |
| 1914 | if (right) { |
| 1915 | btrfs_tree_unlock(right); |
| 1916 | free_extent_buffer(right); |
| 1917 | } |
| 1918 | if (left) { |
| 1919 | if (path->nodes[level] != left) |
| 1920 | btrfs_tree_unlock(left); |
| 1921 | free_extent_buffer(left); |
| 1922 | } |
| 1923 | return ret; |
| 1924 | } |
| 1925 | |
| 1926 | /* Node balancing for insertion. Here we only split or push nodes around |
| 1927 | * when they are completely full. This is also done top down, so we |
| 1928 | * have to be pessimistic. |
| 1929 | */ |
| 1930 | static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, |
| 1931 | struct btrfs_root *root, |
| 1932 | struct btrfs_path *path, int level) |
| 1933 | { |
| 1934 | struct extent_buffer *right = NULL; |
| 1935 | struct extent_buffer *mid; |
| 1936 | struct extent_buffer *left = NULL; |
| 1937 | struct extent_buffer *parent = NULL; |
| 1938 | int ret = 0; |
| 1939 | int wret; |
| 1940 | int pslot; |
| 1941 | int orig_slot = path->slots[level]; |
| 1942 | |
| 1943 | if (level == 0) |
| 1944 | return 1; |
| 1945 | |
| 1946 | mid = path->nodes[level]; |
| 1947 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
| 1948 | |
| 1949 | if (level < BTRFS_MAX_LEVEL - 1) { |
| 1950 | parent = path->nodes[level + 1]; |
| 1951 | pslot = path->slots[level + 1]; |
| 1952 | } |
| 1953 | |
| 1954 | if (!parent) |
| 1955 | return 1; |
| 1956 | |
| 1957 | left = read_node_slot(root, parent, pslot - 1); |
| 1958 | |
| 1959 | /* first, try to make some room in the middle buffer */ |
| 1960 | if (left) { |
| 1961 | u32 left_nr; |
| 1962 | |
| 1963 | btrfs_tree_lock(left); |
| 1964 | btrfs_set_lock_blocking(left); |
| 1965 | |
| 1966 | left_nr = btrfs_header_nritems(left); |
| 1967 | if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { |
| 1968 | wret = 1; |
| 1969 | } else { |
| 1970 | ret = btrfs_cow_block(trans, root, left, parent, |
| 1971 | pslot - 1, &left); |
| 1972 | if (ret) |
| 1973 | wret = 1; |
| 1974 | else { |
| 1975 | wret = push_node_left(trans, root, |
| 1976 | left, mid, 0); |
| 1977 | } |
| 1978 | } |
| 1979 | if (wret < 0) |
| 1980 | ret = wret; |
| 1981 | if (wret == 0) { |
| 1982 | struct btrfs_disk_key disk_key; |
| 1983 | orig_slot += left_nr; |
| 1984 | btrfs_node_key(mid, &disk_key, 0); |
| 1985 | tree_mod_log_set_node_key(root->fs_info, parent, |
| 1986 | pslot, 0); |
| 1987 | btrfs_set_node_key(parent, &disk_key, pslot); |
| 1988 | btrfs_mark_buffer_dirty(parent); |
| 1989 | if (btrfs_header_nritems(left) > orig_slot) { |
| 1990 | path->nodes[level] = left; |
| 1991 | path->slots[level + 1] -= 1; |
| 1992 | path->slots[level] = orig_slot; |
| 1993 | btrfs_tree_unlock(mid); |
| 1994 | free_extent_buffer(mid); |
| 1995 | } else { |
| 1996 | orig_slot -= |
| 1997 | btrfs_header_nritems(left); |
| 1998 | path->slots[level] = orig_slot; |
| 1999 | btrfs_tree_unlock(left); |
| 2000 | free_extent_buffer(left); |
| 2001 | } |
| 2002 | return 0; |
| 2003 | } |
| 2004 | btrfs_tree_unlock(left); |
| 2005 | free_extent_buffer(left); |
| 2006 | } |
| 2007 | right = read_node_slot(root, parent, pslot + 1); |
| 2008 | |
| 2009 | /* |
| 2010 | * then try to empty the right most buffer into the middle |
| 2011 | */ |
| 2012 | if (right) { |
| 2013 | u32 right_nr; |
| 2014 | |
| 2015 | btrfs_tree_lock(right); |
| 2016 | btrfs_set_lock_blocking(right); |
| 2017 | |
| 2018 | right_nr = btrfs_header_nritems(right); |
| 2019 | if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) { |
| 2020 | wret = 1; |
| 2021 | } else { |
| 2022 | ret = btrfs_cow_block(trans, root, right, |
| 2023 | parent, pslot + 1, |
| 2024 | &right); |
| 2025 | if (ret) |
| 2026 | wret = 1; |
| 2027 | else { |
| 2028 | wret = balance_node_right(trans, root, |
| 2029 | right, mid); |
| 2030 | } |
| 2031 | } |
| 2032 | if (wret < 0) |
| 2033 | ret = wret; |
| 2034 | if (wret == 0) { |
| 2035 | struct btrfs_disk_key disk_key; |
| 2036 | |
| 2037 | btrfs_node_key(right, &disk_key, 0); |
| 2038 | tree_mod_log_set_node_key(root->fs_info, parent, |
| 2039 | pslot + 1, 0); |
| 2040 | btrfs_set_node_key(parent, &disk_key, pslot + 1); |
| 2041 | btrfs_mark_buffer_dirty(parent); |
| 2042 | |
| 2043 | if (btrfs_header_nritems(mid) <= orig_slot) { |
| 2044 | path->nodes[level] = right; |
| 2045 | path->slots[level + 1] += 1; |
| 2046 | path->slots[level] = orig_slot - |
| 2047 | btrfs_header_nritems(mid); |
| 2048 | btrfs_tree_unlock(mid); |
| 2049 | free_extent_buffer(mid); |
| 2050 | } else { |
| 2051 | btrfs_tree_unlock(right); |
| 2052 | free_extent_buffer(right); |
| 2053 | } |
| 2054 | return 0; |
| 2055 | } |
| 2056 | btrfs_tree_unlock(right); |
| 2057 | free_extent_buffer(right); |
| 2058 | } |
| 2059 | return 1; |
| 2060 | } |
| 2061 | |
| 2062 | /* |
| 2063 | * readahead one full node of leaves, finding things that are close |
| 2064 | * to the block in 'slot', and triggering ra on them. |
| 2065 | */ |
| 2066 | static void reada_for_search(struct btrfs_root *root, |
| 2067 | struct btrfs_path *path, |
| 2068 | int level, int slot, u64 objectid) |
| 2069 | { |
| 2070 | struct extent_buffer *node; |
| 2071 | struct btrfs_disk_key disk_key; |
| 2072 | u32 nritems; |
| 2073 | u64 search; |
| 2074 | u64 target; |
| 2075 | u64 nread = 0; |
| 2076 | u64 gen; |
| 2077 | int direction = path->reada; |
| 2078 | struct extent_buffer *eb; |
| 2079 | u32 nr; |
| 2080 | u32 blocksize; |
| 2081 | u32 nscan = 0; |
| 2082 | |
| 2083 | if (level != 1) |
| 2084 | return; |
| 2085 | |
| 2086 | if (!path->nodes[level]) |
| 2087 | return; |
| 2088 | |
| 2089 | node = path->nodes[level]; |
| 2090 | |
| 2091 | search = btrfs_node_blockptr(node, slot); |
| 2092 | blocksize = btrfs_level_size(root, level - 1); |
| 2093 | eb = btrfs_find_tree_block(root, search, blocksize); |
| 2094 | if (eb) { |
| 2095 | free_extent_buffer(eb); |
| 2096 | return; |
| 2097 | } |
| 2098 | |
| 2099 | target = search; |
| 2100 | |
| 2101 | nritems = btrfs_header_nritems(node); |
| 2102 | nr = slot; |
| 2103 | |
| 2104 | while (1) { |
| 2105 | if (direction < 0) { |
| 2106 | if (nr == 0) |
| 2107 | break; |
| 2108 | nr--; |
| 2109 | } else if (direction > 0) { |
| 2110 | nr++; |
| 2111 | if (nr >= nritems) |
| 2112 | break; |
| 2113 | } |
| 2114 | if (path->reada < 0 && objectid) { |
| 2115 | btrfs_node_key(node, &disk_key, nr); |
| 2116 | if (btrfs_disk_key_objectid(&disk_key) != objectid) |
| 2117 | break; |
| 2118 | } |
| 2119 | search = btrfs_node_blockptr(node, nr); |
| 2120 | if ((search <= target && target - search <= 65536) || |
| 2121 | (search > target && search - target <= 65536)) { |
| 2122 | gen = btrfs_node_ptr_generation(node, nr); |
| 2123 | readahead_tree_block(root, search, blocksize, gen); |
| 2124 | nread += blocksize; |
| 2125 | } |
| 2126 | nscan++; |
| 2127 | if ((nread > 65536 || nscan > 32)) |
| 2128 | break; |
| 2129 | } |
| 2130 | } |
| 2131 | |
| 2132 | /* |
| 2133 | * returns -EAGAIN if it had to drop the path, or zero if everything was in |
| 2134 | * cache |
| 2135 | */ |
| 2136 | static noinline int reada_for_balance(struct btrfs_root *root, |
| 2137 | struct btrfs_path *path, int level) |
| 2138 | { |
| 2139 | int slot; |
| 2140 | int nritems; |
| 2141 | struct extent_buffer *parent; |
| 2142 | struct extent_buffer *eb; |
| 2143 | u64 gen; |
| 2144 | u64 block1 = 0; |
| 2145 | u64 block2 = 0; |
| 2146 | int ret = 0; |
| 2147 | int blocksize; |
| 2148 | |
| 2149 | parent = path->nodes[level + 1]; |
| 2150 | if (!parent) |
| 2151 | return 0; |
| 2152 | |
| 2153 | nritems = btrfs_header_nritems(parent); |
| 2154 | slot = path->slots[level + 1]; |
| 2155 | blocksize = btrfs_level_size(root, level); |
| 2156 | |
| 2157 | if (slot > 0) { |
| 2158 | block1 = btrfs_node_blockptr(parent, slot - 1); |
| 2159 | gen = btrfs_node_ptr_generation(parent, slot - 1); |
| 2160 | eb = btrfs_find_tree_block(root, block1, blocksize); |
| 2161 | /* |
| 2162 | * if we get -eagain from btrfs_buffer_uptodate, we |
| 2163 | * don't want to return eagain here. That will loop |
| 2164 | * forever |
| 2165 | */ |
| 2166 | if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0) |
| 2167 | block1 = 0; |
| 2168 | free_extent_buffer(eb); |
| 2169 | } |
| 2170 | if (slot + 1 < nritems) { |
| 2171 | block2 = btrfs_node_blockptr(parent, slot + 1); |
| 2172 | gen = btrfs_node_ptr_generation(parent, slot + 1); |
| 2173 | eb = btrfs_find_tree_block(root, block2, blocksize); |
| 2174 | if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0) |
| 2175 | block2 = 0; |
| 2176 | free_extent_buffer(eb); |
| 2177 | } |
| 2178 | if (block1 || block2) { |
| 2179 | ret = -EAGAIN; |
| 2180 | |
| 2181 | /* release the whole path */ |
| 2182 | btrfs_release_path(path); |
| 2183 | |
| 2184 | /* read the blocks */ |
| 2185 | if (block1) |
| 2186 | readahead_tree_block(root, block1, blocksize, 0); |
| 2187 | if (block2) |
| 2188 | readahead_tree_block(root, block2, blocksize, 0); |
| 2189 | |
| 2190 | if (block1) { |
| 2191 | eb = read_tree_block(root, block1, blocksize, 0); |
| 2192 | free_extent_buffer(eb); |
| 2193 | } |
| 2194 | if (block2) { |
| 2195 | eb = read_tree_block(root, block2, blocksize, 0); |
| 2196 | free_extent_buffer(eb); |
| 2197 | } |
| 2198 | } |
| 2199 | return ret; |
| 2200 | } |
| 2201 | |
| 2202 | |
| 2203 | /* |
| 2204 | * when we walk down the tree, it is usually safe to unlock the higher layers |
| 2205 | * in the tree. The exceptions are when our path goes through slot 0, because |
| 2206 | * operations on the tree might require changing key pointers higher up in the |
| 2207 | * tree. |
| 2208 | * |
| 2209 | * callers might also have set path->keep_locks, which tells this code to keep |
| 2210 | * the lock if the path points to the last slot in the block. This is part of |
| 2211 | * walking through the tree, and selecting the next slot in the higher block. |
| 2212 | * |
| 2213 | * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so |
| 2214 | * if lowest_unlock is 1, level 0 won't be unlocked |
| 2215 | */ |
| 2216 | static noinline void unlock_up(struct btrfs_path *path, int level, |
| 2217 | int lowest_unlock, int min_write_lock_level, |
| 2218 | int *write_lock_level) |
| 2219 | { |
| 2220 | int i; |
| 2221 | int skip_level = level; |
| 2222 | int no_skips = 0; |
| 2223 | struct extent_buffer *t; |
| 2224 | |
| 2225 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| 2226 | if (!path->nodes[i]) |
| 2227 | break; |
| 2228 | if (!path->locks[i]) |
| 2229 | break; |
| 2230 | if (!no_skips && path->slots[i] == 0) { |
| 2231 | skip_level = i + 1; |
| 2232 | continue; |
| 2233 | } |
| 2234 | if (!no_skips && path->keep_locks) { |
| 2235 | u32 nritems; |
| 2236 | t = path->nodes[i]; |
| 2237 | nritems = btrfs_header_nritems(t); |
| 2238 | if (nritems < 1 || path->slots[i] >= nritems - 1) { |
| 2239 | skip_level = i + 1; |
| 2240 | continue; |
| 2241 | } |
| 2242 | } |
| 2243 | if (skip_level < i && i >= lowest_unlock) |
| 2244 | no_skips = 1; |
| 2245 | |
| 2246 | t = path->nodes[i]; |
| 2247 | if (i >= lowest_unlock && i > skip_level && path->locks[i]) { |
| 2248 | btrfs_tree_unlock_rw(t, path->locks[i]); |
| 2249 | path->locks[i] = 0; |
| 2250 | if (write_lock_level && |
| 2251 | i > min_write_lock_level && |
| 2252 | i <= *write_lock_level) { |
| 2253 | *write_lock_level = i - 1; |
| 2254 | } |
| 2255 | } |
| 2256 | } |
| 2257 | } |
| 2258 | |
| 2259 | /* |
| 2260 | * This releases any locks held in the path starting at level and |
| 2261 | * going all the way up to the root. |
| 2262 | * |
| 2263 | * btrfs_search_slot will keep the lock held on higher nodes in a few |
| 2264 | * corner cases, such as COW of the block at slot zero in the node. This |
| 2265 | * ignores those rules, and it should only be called when there are no |
| 2266 | * more updates to be done higher up in the tree. |
| 2267 | */ |
| 2268 | noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level) |
| 2269 | { |
| 2270 | int i; |
| 2271 | |
| 2272 | if (path->keep_locks) |
| 2273 | return; |
| 2274 | |
| 2275 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| 2276 | if (!path->nodes[i]) |
| 2277 | continue; |
| 2278 | if (!path->locks[i]) |
| 2279 | continue; |
| 2280 | btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]); |
| 2281 | path->locks[i] = 0; |
| 2282 | } |
| 2283 | } |
| 2284 | |
| 2285 | /* |
| 2286 | * helper function for btrfs_search_slot. The goal is to find a block |
| 2287 | * in cache without setting the path to blocking. If we find the block |
| 2288 | * we return zero and the path is unchanged. |
| 2289 | * |
| 2290 | * If we can't find the block, we set the path blocking and do some |
| 2291 | * reada. -EAGAIN is returned and the search must be repeated. |
| 2292 | */ |
| 2293 | static int |
| 2294 | read_block_for_search(struct btrfs_trans_handle *trans, |
| 2295 | struct btrfs_root *root, struct btrfs_path *p, |
| 2296 | struct extent_buffer **eb_ret, int level, int slot, |
| 2297 | struct btrfs_key *key, u64 time_seq) |
| 2298 | { |
| 2299 | u64 blocknr; |
| 2300 | u64 gen; |
| 2301 | u32 blocksize; |
| 2302 | struct extent_buffer *b = *eb_ret; |
| 2303 | struct extent_buffer *tmp; |
| 2304 | int ret; |
| 2305 | |
| 2306 | blocknr = btrfs_node_blockptr(b, slot); |
| 2307 | gen = btrfs_node_ptr_generation(b, slot); |
| 2308 | blocksize = btrfs_level_size(root, level - 1); |
| 2309 | |
| 2310 | tmp = btrfs_find_tree_block(root, blocknr, blocksize); |
| 2311 | if (tmp) { |
| 2312 | /* first we do an atomic uptodate check */ |
| 2313 | if (btrfs_buffer_uptodate(tmp, 0, 1) > 0) { |
| 2314 | if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) { |
| 2315 | /* |
| 2316 | * we found an up to date block without |
| 2317 | * sleeping, return |
| 2318 | * right away |
| 2319 | */ |
| 2320 | *eb_ret = tmp; |
| 2321 | return 0; |
| 2322 | } |
| 2323 | /* the pages were up to date, but we failed |
| 2324 | * the generation number check. Do a full |
| 2325 | * read for the generation number that is correct. |
| 2326 | * We must do this without dropping locks so |
| 2327 | * we can trust our generation number |
| 2328 | */ |
| 2329 | free_extent_buffer(tmp); |
| 2330 | btrfs_set_path_blocking(p); |
| 2331 | |
| 2332 | /* now we're allowed to do a blocking uptodate check */ |
| 2333 | tmp = read_tree_block(root, blocknr, blocksize, gen); |
| 2334 | if (tmp && btrfs_buffer_uptodate(tmp, gen, 0) > 0) { |
| 2335 | *eb_ret = tmp; |
| 2336 | return 0; |
| 2337 | } |
| 2338 | free_extent_buffer(tmp); |
| 2339 | btrfs_release_path(p); |
| 2340 | return -EIO; |
| 2341 | } |
| 2342 | } |
| 2343 | |
| 2344 | /* |
| 2345 | * reduce lock contention at high levels |
| 2346 | * of the btree by dropping locks before |
| 2347 | * we read. Don't release the lock on the current |
| 2348 | * level because we need to walk this node to figure |
| 2349 | * out which blocks to read. |
| 2350 | */ |
| 2351 | btrfs_unlock_up_safe(p, level + 1); |
| 2352 | btrfs_set_path_blocking(p); |
| 2353 | |
| 2354 | free_extent_buffer(tmp); |
| 2355 | if (p->reada) |
| 2356 | reada_for_search(root, p, level, slot, key->objectid); |
| 2357 | |
| 2358 | btrfs_release_path(p); |
| 2359 | |
| 2360 | ret = -EAGAIN; |
| 2361 | tmp = read_tree_block(root, blocknr, blocksize, 0); |
| 2362 | if (tmp) { |
| 2363 | /* |
| 2364 | * If the read above didn't mark this buffer up to date, |
| 2365 | * it will never end up being up to date. Set ret to EIO now |
| 2366 | * and give up so that our caller doesn't loop forever |
| 2367 | * on our EAGAINs. |
| 2368 | */ |
| 2369 | if (!btrfs_buffer_uptodate(tmp, 0, 0)) |
| 2370 | ret = -EIO; |
| 2371 | free_extent_buffer(tmp); |
| 2372 | } |
| 2373 | return ret; |
| 2374 | } |
| 2375 | |
| 2376 | /* |
| 2377 | * helper function for btrfs_search_slot. This does all of the checks |
| 2378 | * for node-level blocks and does any balancing required based on |
| 2379 | * the ins_len. |
| 2380 | * |
| 2381 | * If no extra work was required, zero is returned. If we had to |
| 2382 | * drop the path, -EAGAIN is returned and btrfs_search_slot must |
| 2383 | * start over |
| 2384 | */ |
| 2385 | static int |
| 2386 | setup_nodes_for_search(struct btrfs_trans_handle *trans, |
| 2387 | struct btrfs_root *root, struct btrfs_path *p, |
| 2388 | struct extent_buffer *b, int level, int ins_len, |
| 2389 | int *write_lock_level) |
| 2390 | { |
| 2391 | int ret; |
| 2392 | if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= |
| 2393 | BTRFS_NODEPTRS_PER_BLOCK(root) - 3) { |
| 2394 | int sret; |
| 2395 | |
| 2396 | if (*write_lock_level < level + 1) { |
| 2397 | *write_lock_level = level + 1; |
| 2398 | btrfs_release_path(p); |
| 2399 | goto again; |
| 2400 | } |
| 2401 | |
| 2402 | sret = reada_for_balance(root, p, level); |
| 2403 | if (sret) |
| 2404 | goto again; |
| 2405 | |
| 2406 | btrfs_set_path_blocking(p); |
| 2407 | sret = split_node(trans, root, p, level); |
| 2408 | btrfs_clear_path_blocking(p, NULL, 0); |
| 2409 | |
| 2410 | BUG_ON(sret > 0); |
| 2411 | if (sret) { |
| 2412 | ret = sret; |
| 2413 | goto done; |
| 2414 | } |
| 2415 | b = p->nodes[level]; |
| 2416 | } else if (ins_len < 0 && btrfs_header_nritems(b) < |
| 2417 | BTRFS_NODEPTRS_PER_BLOCK(root) / 2) { |
| 2418 | int sret; |
| 2419 | |
| 2420 | if (*write_lock_level < level + 1) { |
| 2421 | *write_lock_level = level + 1; |
| 2422 | btrfs_release_path(p); |
| 2423 | goto again; |
| 2424 | } |
| 2425 | |
| 2426 | sret = reada_for_balance(root, p, level); |
| 2427 | if (sret) |
| 2428 | goto again; |
| 2429 | |
| 2430 | btrfs_set_path_blocking(p); |
| 2431 | sret = balance_level(trans, root, p, level); |
| 2432 | btrfs_clear_path_blocking(p, NULL, 0); |
| 2433 | |
| 2434 | if (sret) { |
| 2435 | ret = sret; |
| 2436 | goto done; |
| 2437 | } |
| 2438 | b = p->nodes[level]; |
| 2439 | if (!b) { |
| 2440 | btrfs_release_path(p); |
| 2441 | goto again; |
| 2442 | } |
| 2443 | BUG_ON(btrfs_header_nritems(b) == 1); |
| 2444 | } |
| 2445 | return 0; |
| 2446 | |
| 2447 | again: |
| 2448 | ret = -EAGAIN; |
| 2449 | done: |
| 2450 | return ret; |
| 2451 | } |
| 2452 | |
| 2453 | /* |
| 2454 | * look for key in the tree. path is filled in with nodes along the way |
| 2455 | * if key is found, we return zero and you can find the item in the leaf |
| 2456 | * level of the path (level 0) |
| 2457 | * |
| 2458 | * If the key isn't found, the path points to the slot where it should |
| 2459 | * be inserted, and 1 is returned. If there are other errors during the |
| 2460 | * search a negative error number is returned. |
| 2461 | * |
| 2462 | * if ins_len > 0, nodes and leaves will be split as we walk down the |
| 2463 | * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if |
| 2464 | * possible) |
| 2465 | */ |
| 2466 | int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root |
| 2467 | *root, struct btrfs_key *key, struct btrfs_path *p, int |
| 2468 | ins_len, int cow) |
| 2469 | { |
| 2470 | struct extent_buffer *b; |
| 2471 | int slot; |
| 2472 | int ret; |
| 2473 | int err; |
| 2474 | int level; |
| 2475 | int lowest_unlock = 1; |
| 2476 | int root_lock; |
| 2477 | /* everything at write_lock_level or lower must be write locked */ |
| 2478 | int write_lock_level = 0; |
| 2479 | u8 lowest_level = 0; |
| 2480 | int min_write_lock_level; |
| 2481 | |
| 2482 | lowest_level = p->lowest_level; |
| 2483 | WARN_ON(lowest_level && ins_len > 0); |
| 2484 | WARN_ON(p->nodes[0] != NULL); |
| 2485 | |
| 2486 | if (ins_len < 0) { |
| 2487 | lowest_unlock = 2; |
| 2488 | |
| 2489 | /* when we are removing items, we might have to go up to level |
| 2490 | * two as we update tree pointers Make sure we keep write |
| 2491 | * for those levels as well |
| 2492 | */ |
| 2493 | write_lock_level = 2; |
| 2494 | } else if (ins_len > 0) { |
| 2495 | /* |
| 2496 | * for inserting items, make sure we have a write lock on |
| 2497 | * level 1 so we can update keys |
| 2498 | */ |
| 2499 | write_lock_level = 1; |
| 2500 | } |
| 2501 | |
| 2502 | if (!cow) |
| 2503 | write_lock_level = -1; |
| 2504 | |
| 2505 | if (cow && (p->keep_locks || p->lowest_level)) |
| 2506 | write_lock_level = BTRFS_MAX_LEVEL; |
| 2507 | |
| 2508 | min_write_lock_level = write_lock_level; |
| 2509 | |
| 2510 | again: |
| 2511 | /* |
| 2512 | * we try very hard to do read locks on the root |
| 2513 | */ |
| 2514 | root_lock = BTRFS_READ_LOCK; |
| 2515 | level = 0; |
| 2516 | if (p->search_commit_root) { |
| 2517 | /* |
| 2518 | * the commit roots are read only |
| 2519 | * so we always do read locks |
| 2520 | */ |
| 2521 | b = root->commit_root; |
| 2522 | extent_buffer_get(b); |
| 2523 | level = btrfs_header_level(b); |
| 2524 | if (!p->skip_locking) |
| 2525 | btrfs_tree_read_lock(b); |
| 2526 | } else { |
| 2527 | if (p->skip_locking) { |
| 2528 | b = btrfs_root_node(root); |
| 2529 | level = btrfs_header_level(b); |
| 2530 | } else { |
| 2531 | /* we don't know the level of the root node |
| 2532 | * until we actually have it read locked |
| 2533 | */ |
| 2534 | b = btrfs_read_lock_root_node(root); |
| 2535 | level = btrfs_header_level(b); |
| 2536 | if (level <= write_lock_level) { |
| 2537 | /* whoops, must trade for write lock */ |
| 2538 | btrfs_tree_read_unlock(b); |
| 2539 | free_extent_buffer(b); |
| 2540 | b = btrfs_lock_root_node(root); |
| 2541 | root_lock = BTRFS_WRITE_LOCK; |
| 2542 | |
| 2543 | /* the level might have changed, check again */ |
| 2544 | level = btrfs_header_level(b); |
| 2545 | } |
| 2546 | } |
| 2547 | } |
| 2548 | p->nodes[level] = b; |
| 2549 | if (!p->skip_locking) |
| 2550 | p->locks[level] = root_lock; |
| 2551 | |
| 2552 | while (b) { |
| 2553 | level = btrfs_header_level(b); |
| 2554 | |
| 2555 | /* |
| 2556 | * setup the path here so we can release it under lock |
| 2557 | * contention with the cow code |
| 2558 | */ |
| 2559 | if (cow) { |
| 2560 | /* |
| 2561 | * if we don't really need to cow this block |
| 2562 | * then we don't want to set the path blocking, |
| 2563 | * so we test it here |
| 2564 | */ |
| 2565 | if (!should_cow_block(trans, root, b)) |
| 2566 | goto cow_done; |
| 2567 | |
| 2568 | btrfs_set_path_blocking(p); |
| 2569 | |
| 2570 | /* |
| 2571 | * must have write locks on this node and the |
| 2572 | * parent |
| 2573 | */ |
| 2574 | if (level > write_lock_level || |
| 2575 | (level + 1 > write_lock_level && |
| 2576 | level + 1 < BTRFS_MAX_LEVEL && |
| 2577 | p->nodes[level + 1])) { |
| 2578 | write_lock_level = level + 1; |
| 2579 | btrfs_release_path(p); |
| 2580 | goto again; |
| 2581 | } |
| 2582 | |
| 2583 | err = btrfs_cow_block(trans, root, b, |
| 2584 | p->nodes[level + 1], |
| 2585 | p->slots[level + 1], &b); |
| 2586 | if (err) { |
| 2587 | ret = err; |
| 2588 | goto done; |
| 2589 | } |
| 2590 | } |
| 2591 | cow_done: |
| 2592 | BUG_ON(!cow && ins_len); |
| 2593 | |
| 2594 | p->nodes[level] = b; |
| 2595 | btrfs_clear_path_blocking(p, NULL, 0); |
| 2596 | |
| 2597 | /* |
| 2598 | * we have a lock on b and as long as we aren't changing |
| 2599 | * the tree, there is no way to for the items in b to change. |
| 2600 | * It is safe to drop the lock on our parent before we |
| 2601 | * go through the expensive btree search on b. |
| 2602 | * |
| 2603 | * If cow is true, then we might be changing slot zero, |
| 2604 | * which may require changing the parent. So, we can't |
| 2605 | * drop the lock until after we know which slot we're |
| 2606 | * operating on. |
| 2607 | */ |
| 2608 | if (!cow) |
| 2609 | btrfs_unlock_up_safe(p, level + 1); |
| 2610 | |
| 2611 | ret = bin_search(b, key, level, &slot); |
| 2612 | |
| 2613 | if (level != 0) { |
| 2614 | int dec = 0; |
| 2615 | if (ret && slot > 0) { |
| 2616 | dec = 1; |
| 2617 | slot -= 1; |
| 2618 | } |
| 2619 | p->slots[level] = slot; |
| 2620 | err = setup_nodes_for_search(trans, root, p, b, level, |
| 2621 | ins_len, &write_lock_level); |
| 2622 | if (err == -EAGAIN) |
| 2623 | goto again; |
| 2624 | if (err) { |
| 2625 | ret = err; |
| 2626 | goto done; |
| 2627 | } |
| 2628 | b = p->nodes[level]; |
| 2629 | slot = p->slots[level]; |
| 2630 | |
| 2631 | /* |
| 2632 | * slot 0 is special, if we change the key |
| 2633 | * we have to update the parent pointer |
| 2634 | * which means we must have a write lock |
| 2635 | * on the parent |
| 2636 | */ |
| 2637 | if (slot == 0 && cow && |
| 2638 | write_lock_level < level + 1) { |
| 2639 | write_lock_level = level + 1; |
| 2640 | btrfs_release_path(p); |
| 2641 | goto again; |
| 2642 | } |
| 2643 | |
| 2644 | unlock_up(p, level, lowest_unlock, |
| 2645 | min_write_lock_level, &write_lock_level); |
| 2646 | |
| 2647 | if (level == lowest_level) { |
| 2648 | if (dec) |
| 2649 | p->slots[level]++; |
| 2650 | goto done; |
| 2651 | } |
| 2652 | |
| 2653 | err = read_block_for_search(trans, root, p, |
| 2654 | &b, level, slot, key, 0); |
| 2655 | if (err == -EAGAIN) |
| 2656 | goto again; |
| 2657 | if (err) { |
| 2658 | ret = err; |
| 2659 | goto done; |
| 2660 | } |
| 2661 | |
| 2662 | if (!p->skip_locking) { |
| 2663 | level = btrfs_header_level(b); |
| 2664 | if (level <= write_lock_level) { |
| 2665 | err = btrfs_try_tree_write_lock(b); |
| 2666 | if (!err) { |
| 2667 | btrfs_set_path_blocking(p); |
| 2668 | btrfs_tree_lock(b); |
| 2669 | btrfs_clear_path_blocking(p, b, |
| 2670 | BTRFS_WRITE_LOCK); |
| 2671 | } |
| 2672 | p->locks[level] = BTRFS_WRITE_LOCK; |
| 2673 | } else { |
| 2674 | err = btrfs_try_tree_read_lock(b); |
| 2675 | if (!err) { |
| 2676 | btrfs_set_path_blocking(p); |
| 2677 | btrfs_tree_read_lock(b); |
| 2678 | btrfs_clear_path_blocking(p, b, |
| 2679 | BTRFS_READ_LOCK); |
| 2680 | } |
| 2681 | p->locks[level] = BTRFS_READ_LOCK; |
| 2682 | } |
| 2683 | p->nodes[level] = b; |
| 2684 | } |
| 2685 | } else { |
| 2686 | p->slots[level] = slot; |
| 2687 | if (ins_len > 0 && |
| 2688 | btrfs_leaf_free_space(root, b) < ins_len) { |
| 2689 | if (write_lock_level < 1) { |
| 2690 | write_lock_level = 1; |
| 2691 | btrfs_release_path(p); |
| 2692 | goto again; |
| 2693 | } |
| 2694 | |
| 2695 | btrfs_set_path_blocking(p); |
| 2696 | err = split_leaf(trans, root, key, |
| 2697 | p, ins_len, ret == 0); |
| 2698 | btrfs_clear_path_blocking(p, NULL, 0); |
| 2699 | |
| 2700 | BUG_ON(err > 0); |
| 2701 | if (err) { |
| 2702 | ret = err; |
| 2703 | goto done; |
| 2704 | } |
| 2705 | } |
| 2706 | if (!p->search_for_split) |
| 2707 | unlock_up(p, level, lowest_unlock, |
| 2708 | min_write_lock_level, &write_lock_level); |
| 2709 | goto done; |
| 2710 | } |
| 2711 | } |
| 2712 | ret = 1; |
| 2713 | done: |
| 2714 | /* |
| 2715 | * we don't really know what they plan on doing with the path |
| 2716 | * from here on, so for now just mark it as blocking |
| 2717 | */ |
| 2718 | if (!p->leave_spinning) |
| 2719 | btrfs_set_path_blocking(p); |
| 2720 | if (ret < 0) |
| 2721 | btrfs_release_path(p); |
| 2722 | return ret; |
| 2723 | } |
| 2724 | |
| 2725 | /* |
| 2726 | * Like btrfs_search_slot, this looks for a key in the given tree. It uses the |
| 2727 | * current state of the tree together with the operations recorded in the tree |
| 2728 | * modification log to search for the key in a previous version of this tree, as |
| 2729 | * denoted by the time_seq parameter. |
| 2730 | * |
| 2731 | * Naturally, there is no support for insert, delete or cow operations. |
| 2732 | * |
| 2733 | * The resulting path and return value will be set up as if we called |
| 2734 | * btrfs_search_slot at that point in time with ins_len and cow both set to 0. |
| 2735 | */ |
| 2736 | int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key, |
| 2737 | struct btrfs_path *p, u64 time_seq) |
| 2738 | { |
| 2739 | struct extent_buffer *b; |
| 2740 | int slot; |
| 2741 | int ret; |
| 2742 | int err; |
| 2743 | int level; |
| 2744 | int lowest_unlock = 1; |
| 2745 | u8 lowest_level = 0; |
| 2746 | |
| 2747 | lowest_level = p->lowest_level; |
| 2748 | WARN_ON(p->nodes[0] != NULL); |
| 2749 | |
| 2750 | if (p->search_commit_root) { |
| 2751 | BUG_ON(time_seq); |
| 2752 | return btrfs_search_slot(NULL, root, key, p, 0, 0); |
| 2753 | } |
| 2754 | |
| 2755 | again: |
| 2756 | b = get_old_root(root, time_seq); |
| 2757 | level = btrfs_header_level(b); |
| 2758 | p->locks[level] = BTRFS_READ_LOCK; |
| 2759 | |
| 2760 | while (b) { |
| 2761 | level = btrfs_header_level(b); |
| 2762 | p->nodes[level] = b; |
| 2763 | btrfs_clear_path_blocking(p, NULL, 0); |
| 2764 | |
| 2765 | /* |
| 2766 | * we have a lock on b and as long as we aren't changing |
| 2767 | * the tree, there is no way to for the items in b to change. |
| 2768 | * It is safe to drop the lock on our parent before we |
| 2769 | * go through the expensive btree search on b. |
| 2770 | */ |
| 2771 | btrfs_unlock_up_safe(p, level + 1); |
| 2772 | |
| 2773 | ret = bin_search(b, key, level, &slot); |
| 2774 | |
| 2775 | if (level != 0) { |
| 2776 | int dec = 0; |
| 2777 | if (ret && slot > 0) { |
| 2778 | dec = 1; |
| 2779 | slot -= 1; |
| 2780 | } |
| 2781 | p->slots[level] = slot; |
| 2782 | unlock_up(p, level, lowest_unlock, 0, NULL); |
| 2783 | |
| 2784 | if (level == lowest_level) { |
| 2785 | if (dec) |
| 2786 | p->slots[level]++; |
| 2787 | goto done; |
| 2788 | } |
| 2789 | |
| 2790 | err = read_block_for_search(NULL, root, p, &b, level, |
| 2791 | slot, key, time_seq); |
| 2792 | if (err == -EAGAIN) |
| 2793 | goto again; |
| 2794 | if (err) { |
| 2795 | ret = err; |
| 2796 | goto done; |
| 2797 | } |
| 2798 | |
| 2799 | level = btrfs_header_level(b); |
| 2800 | err = btrfs_try_tree_read_lock(b); |
| 2801 | if (!err) { |
| 2802 | btrfs_set_path_blocking(p); |
| 2803 | btrfs_tree_read_lock(b); |
| 2804 | btrfs_clear_path_blocking(p, b, |
| 2805 | BTRFS_READ_LOCK); |
| 2806 | } |
| 2807 | b = tree_mod_log_rewind(root->fs_info, b, time_seq); |
| 2808 | p->locks[level] = BTRFS_READ_LOCK; |
| 2809 | p->nodes[level] = b; |
| 2810 | } else { |
| 2811 | p->slots[level] = slot; |
| 2812 | unlock_up(p, level, lowest_unlock, 0, NULL); |
| 2813 | goto done; |
| 2814 | } |
| 2815 | } |
| 2816 | ret = 1; |
| 2817 | done: |
| 2818 | if (!p->leave_spinning) |
| 2819 | btrfs_set_path_blocking(p); |
| 2820 | if (ret < 0) |
| 2821 | btrfs_release_path(p); |
| 2822 | |
| 2823 | return ret; |
| 2824 | } |
| 2825 | |
| 2826 | /* |
| 2827 | * helper to use instead of search slot if no exact match is needed but |
| 2828 | * instead the next or previous item should be returned. |
| 2829 | * When find_higher is true, the next higher item is returned, the next lower |
| 2830 | * otherwise. |
| 2831 | * When return_any and find_higher are both true, and no higher item is found, |
| 2832 | * return the next lower instead. |
| 2833 | * When return_any is true and find_higher is false, and no lower item is found, |
| 2834 | * return the next higher instead. |
| 2835 | * It returns 0 if any item is found, 1 if none is found (tree empty), and |
| 2836 | * < 0 on error |
| 2837 | */ |
| 2838 | int btrfs_search_slot_for_read(struct btrfs_root *root, |
| 2839 | struct btrfs_key *key, struct btrfs_path *p, |
| 2840 | int find_higher, int return_any) |
| 2841 | { |
| 2842 | int ret; |
| 2843 | struct extent_buffer *leaf; |
| 2844 | |
| 2845 | again: |
| 2846 | ret = btrfs_search_slot(NULL, root, key, p, 0, 0); |
| 2847 | if (ret <= 0) |
| 2848 | return ret; |
| 2849 | /* |
| 2850 | * a return value of 1 means the path is at the position where the |
| 2851 | * item should be inserted. Normally this is the next bigger item, |
| 2852 | * but in case the previous item is the last in a leaf, path points |
| 2853 | * to the first free slot in the previous leaf, i.e. at an invalid |
| 2854 | * item. |
| 2855 | */ |
| 2856 | leaf = p->nodes[0]; |
| 2857 | |
| 2858 | if (find_higher) { |
| 2859 | if (p->slots[0] >= btrfs_header_nritems(leaf)) { |
| 2860 | ret = btrfs_next_leaf(root, p); |
| 2861 | if (ret <= 0) |
| 2862 | return ret; |
| 2863 | if (!return_any) |
| 2864 | return 1; |
| 2865 | /* |
| 2866 | * no higher item found, return the next |
| 2867 | * lower instead |
| 2868 | */ |
| 2869 | return_any = 0; |
| 2870 | find_higher = 0; |
| 2871 | btrfs_release_path(p); |
| 2872 | goto again; |
| 2873 | } |
| 2874 | } else { |
| 2875 | if (p->slots[0] == 0) { |
| 2876 | ret = btrfs_prev_leaf(root, p); |
| 2877 | if (ret < 0) |
| 2878 | return ret; |
| 2879 | if (!ret) { |
| 2880 | p->slots[0] = btrfs_header_nritems(leaf) - 1; |
| 2881 | return 0; |
| 2882 | } |
| 2883 | if (!return_any) |
| 2884 | return 1; |
| 2885 | /* |
| 2886 | * no lower item found, return the next |
| 2887 | * higher instead |
| 2888 | */ |
| 2889 | return_any = 0; |
| 2890 | find_higher = 1; |
| 2891 | btrfs_release_path(p); |
| 2892 | goto again; |
| 2893 | } else { |
| 2894 | --p->slots[0]; |
| 2895 | } |
| 2896 | } |
| 2897 | return 0; |
| 2898 | } |
| 2899 | |
| 2900 | /* |
| 2901 | * adjust the pointers going up the tree, starting at level |
| 2902 | * making sure the right key of each node is points to 'key'. |
| 2903 | * This is used after shifting pointers to the left, so it stops |
| 2904 | * fixing up pointers when a given leaf/node is not in slot 0 of the |
| 2905 | * higher levels |
| 2906 | * |
| 2907 | */ |
| 2908 | static void fixup_low_keys(struct btrfs_trans_handle *trans, |
| 2909 | struct btrfs_root *root, struct btrfs_path *path, |
| 2910 | struct btrfs_disk_key *key, int level) |
| 2911 | { |
| 2912 | int i; |
| 2913 | struct extent_buffer *t; |
| 2914 | |
| 2915 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| 2916 | int tslot = path->slots[i]; |
| 2917 | if (!path->nodes[i]) |
| 2918 | break; |
| 2919 | t = path->nodes[i]; |
| 2920 | tree_mod_log_set_node_key(root->fs_info, t, tslot, 1); |
| 2921 | btrfs_set_node_key(t, key, tslot); |
| 2922 | btrfs_mark_buffer_dirty(path->nodes[i]); |
| 2923 | if (tslot != 0) |
| 2924 | break; |
| 2925 | } |
| 2926 | } |
| 2927 | |
| 2928 | /* |
| 2929 | * update item key. |
| 2930 | * |
| 2931 | * This function isn't completely safe. It's the caller's responsibility |
| 2932 | * that the new key won't break the order |
| 2933 | */ |
| 2934 | void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, |
| 2935 | struct btrfs_root *root, struct btrfs_path *path, |
| 2936 | struct btrfs_key *new_key) |
| 2937 | { |
| 2938 | struct btrfs_disk_key disk_key; |
| 2939 | struct extent_buffer *eb; |
| 2940 | int slot; |
| 2941 | |
| 2942 | eb = path->nodes[0]; |
| 2943 | slot = path->slots[0]; |
| 2944 | if (slot > 0) { |
| 2945 | btrfs_item_key(eb, &disk_key, slot - 1); |
| 2946 | BUG_ON(comp_keys(&disk_key, new_key) >= 0); |
| 2947 | } |
| 2948 | if (slot < btrfs_header_nritems(eb) - 1) { |
| 2949 | btrfs_item_key(eb, &disk_key, slot + 1); |
| 2950 | BUG_ON(comp_keys(&disk_key, new_key) <= 0); |
| 2951 | } |
| 2952 | |
| 2953 | btrfs_cpu_key_to_disk(&disk_key, new_key); |
| 2954 | btrfs_set_item_key(eb, &disk_key, slot); |
| 2955 | btrfs_mark_buffer_dirty(eb); |
| 2956 | if (slot == 0) |
| 2957 | fixup_low_keys(trans, root, path, &disk_key, 1); |
| 2958 | } |
| 2959 | |
| 2960 | /* |
| 2961 | * try to push data from one node into the next node left in the |
| 2962 | * tree. |
| 2963 | * |
| 2964 | * returns 0 if some ptrs were pushed left, < 0 if there was some horrible |
| 2965 | * error, and > 0 if there was no room in the left hand block. |
| 2966 | */ |
| 2967 | static int push_node_left(struct btrfs_trans_handle *trans, |
| 2968 | struct btrfs_root *root, struct extent_buffer *dst, |
| 2969 | struct extent_buffer *src, int empty) |
| 2970 | { |
| 2971 | int push_items = 0; |
| 2972 | int src_nritems; |
| 2973 | int dst_nritems; |
| 2974 | int ret = 0; |
| 2975 | |
| 2976 | src_nritems = btrfs_header_nritems(src); |
| 2977 | dst_nritems = btrfs_header_nritems(dst); |
| 2978 | push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems; |
| 2979 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
| 2980 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
| 2981 | |
| 2982 | if (!empty && src_nritems <= 8) |
| 2983 | return 1; |
| 2984 | |
| 2985 | if (push_items <= 0) |
| 2986 | return 1; |
| 2987 | |
| 2988 | if (empty) { |
| 2989 | push_items = min(src_nritems, push_items); |
| 2990 | if (push_items < src_nritems) { |
| 2991 | /* leave at least 8 pointers in the node if |
| 2992 | * we aren't going to empty it |
| 2993 | */ |
| 2994 | if (src_nritems - push_items < 8) { |
| 2995 | if (push_items <= 8) |
| 2996 | return 1; |
| 2997 | push_items -= 8; |
| 2998 | } |
| 2999 | } |
| 3000 | } else |
| 3001 | push_items = min(src_nritems - 8, push_items); |
| 3002 | |
| 3003 | tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0, |
| 3004 | push_items); |
| 3005 | copy_extent_buffer(dst, src, |
| 3006 | btrfs_node_key_ptr_offset(dst_nritems), |
| 3007 | btrfs_node_key_ptr_offset(0), |
| 3008 | push_items * sizeof(struct btrfs_key_ptr)); |
| 3009 | |
| 3010 | if (push_items < src_nritems) { |
| 3011 | /* |
| 3012 | * don't call tree_mod_log_eb_move here, key removal was already |
| 3013 | * fully logged by tree_mod_log_eb_copy above. |
| 3014 | */ |
| 3015 | memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0), |
| 3016 | btrfs_node_key_ptr_offset(push_items), |
| 3017 | (src_nritems - push_items) * |
| 3018 | sizeof(struct btrfs_key_ptr)); |
| 3019 | } |
| 3020 | btrfs_set_header_nritems(src, src_nritems - push_items); |
| 3021 | btrfs_set_header_nritems(dst, dst_nritems + push_items); |
| 3022 | btrfs_mark_buffer_dirty(src); |
| 3023 | btrfs_mark_buffer_dirty(dst); |
| 3024 | |
| 3025 | return ret; |
| 3026 | } |
| 3027 | |
| 3028 | /* |
| 3029 | * try to push data from one node into the next node right in the |
| 3030 | * tree. |
| 3031 | * |
| 3032 | * returns 0 if some ptrs were pushed, < 0 if there was some horrible |
| 3033 | * error, and > 0 if there was no room in the right hand block. |
| 3034 | * |
| 3035 | * this will only push up to 1/2 the contents of the left node over |
| 3036 | */ |
| 3037 | static int balance_node_right(struct btrfs_trans_handle *trans, |
| 3038 | struct btrfs_root *root, |
| 3039 | struct extent_buffer *dst, |
| 3040 | struct extent_buffer *src) |
| 3041 | { |
| 3042 | int push_items = 0; |
| 3043 | int max_push; |
| 3044 | int src_nritems; |
| 3045 | int dst_nritems; |
| 3046 | int ret = 0; |
| 3047 | |
| 3048 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
| 3049 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
| 3050 | |
| 3051 | src_nritems = btrfs_header_nritems(src); |
| 3052 | dst_nritems = btrfs_header_nritems(dst); |
| 3053 | push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems; |
| 3054 | if (push_items <= 0) |
| 3055 | return 1; |
| 3056 | |
| 3057 | if (src_nritems < 4) |
| 3058 | return 1; |
| 3059 | |
| 3060 | max_push = src_nritems / 2 + 1; |
| 3061 | /* don't try to empty the node */ |
| 3062 | if (max_push >= src_nritems) |
| 3063 | return 1; |
| 3064 | |
| 3065 | if (max_push < push_items) |
| 3066 | push_items = max_push; |
| 3067 | |
| 3068 | tree_mod_log_eb_move(root->fs_info, dst, push_items, 0, dst_nritems); |
| 3069 | memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items), |
| 3070 | btrfs_node_key_ptr_offset(0), |
| 3071 | (dst_nritems) * |
| 3072 | sizeof(struct btrfs_key_ptr)); |
| 3073 | |
| 3074 | tree_mod_log_eb_copy(root->fs_info, dst, src, 0, |
| 3075 | src_nritems - push_items, push_items); |
| 3076 | copy_extent_buffer(dst, src, |
| 3077 | btrfs_node_key_ptr_offset(0), |
| 3078 | btrfs_node_key_ptr_offset(src_nritems - push_items), |
| 3079 | push_items * sizeof(struct btrfs_key_ptr)); |
| 3080 | |
| 3081 | btrfs_set_header_nritems(src, src_nritems - push_items); |
| 3082 | btrfs_set_header_nritems(dst, dst_nritems + push_items); |
| 3083 | |
| 3084 | btrfs_mark_buffer_dirty(src); |
| 3085 | btrfs_mark_buffer_dirty(dst); |
| 3086 | |
| 3087 | return ret; |
| 3088 | } |
| 3089 | |
| 3090 | /* |
| 3091 | * helper function to insert a new root level in the tree. |
| 3092 | * A new node is allocated, and a single item is inserted to |
| 3093 | * point to the existing root |
| 3094 | * |
| 3095 | * returns zero on success or < 0 on failure. |
| 3096 | */ |
| 3097 | static noinline int insert_new_root(struct btrfs_trans_handle *trans, |
| 3098 | struct btrfs_root *root, |
| 3099 | struct btrfs_path *path, int level, int log_removal) |
| 3100 | { |
| 3101 | u64 lower_gen; |
| 3102 | struct extent_buffer *lower; |
| 3103 | struct extent_buffer *c; |
| 3104 | struct extent_buffer *old; |
| 3105 | struct btrfs_disk_key lower_key; |
| 3106 | |
| 3107 | BUG_ON(path->nodes[level]); |
| 3108 | BUG_ON(path->nodes[level-1] != root->node); |
| 3109 | |
| 3110 | lower = path->nodes[level-1]; |
| 3111 | if (level == 1) |
| 3112 | btrfs_item_key(lower, &lower_key, 0); |
| 3113 | else |
| 3114 | btrfs_node_key(lower, &lower_key, 0); |
| 3115 | |
| 3116 | c = btrfs_alloc_free_block(trans, root, root->nodesize, 0, |
| 3117 | root->root_key.objectid, &lower_key, |
| 3118 | level, root->node->start, 0); |
| 3119 | if (IS_ERR(c)) |
| 3120 | return PTR_ERR(c); |
| 3121 | |
| 3122 | root_add_used(root, root->nodesize); |
| 3123 | |
| 3124 | memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header)); |
| 3125 | btrfs_set_header_nritems(c, 1); |
| 3126 | btrfs_set_header_level(c, level); |
| 3127 | btrfs_set_header_bytenr(c, c->start); |
| 3128 | btrfs_set_header_generation(c, trans->transid); |
| 3129 | btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV); |
| 3130 | btrfs_set_header_owner(c, root->root_key.objectid); |
| 3131 | |
| 3132 | write_extent_buffer(c, root->fs_info->fsid, |
| 3133 | (unsigned long)btrfs_header_fsid(c), |
| 3134 | BTRFS_FSID_SIZE); |
| 3135 | |
| 3136 | write_extent_buffer(c, root->fs_info->chunk_tree_uuid, |
| 3137 | (unsigned long)btrfs_header_chunk_tree_uuid(c), |
| 3138 | BTRFS_UUID_SIZE); |
| 3139 | |
| 3140 | btrfs_set_node_key(c, &lower_key, 0); |
| 3141 | btrfs_set_node_blockptr(c, 0, lower->start); |
| 3142 | lower_gen = btrfs_header_generation(lower); |
| 3143 | WARN_ON(lower_gen != trans->transid); |
| 3144 | |
| 3145 | btrfs_set_node_ptr_generation(c, 0, lower_gen); |
| 3146 | |
| 3147 | btrfs_mark_buffer_dirty(c); |
| 3148 | |
| 3149 | old = root->node; |
| 3150 | tree_mod_log_set_root_pointer(root, c, log_removal); |
| 3151 | rcu_assign_pointer(root->node, c); |
| 3152 | |
| 3153 | /* the super has an extra ref to root->node */ |
| 3154 | free_extent_buffer(old); |
| 3155 | |
| 3156 | add_root_to_dirty_list(root); |
| 3157 | extent_buffer_get(c); |
| 3158 | path->nodes[level] = c; |
| 3159 | path->locks[level] = BTRFS_WRITE_LOCK; |
| 3160 | path->slots[level] = 0; |
| 3161 | return 0; |
| 3162 | } |
| 3163 | |
| 3164 | /* |
| 3165 | * worker function to insert a single pointer in a node. |
| 3166 | * the node should have enough room for the pointer already |
| 3167 | * |
| 3168 | * slot and level indicate where you want the key to go, and |
| 3169 | * blocknr is the block the key points to. |
| 3170 | */ |
| 3171 | static void insert_ptr(struct btrfs_trans_handle *trans, |
| 3172 | struct btrfs_root *root, struct btrfs_path *path, |
| 3173 | struct btrfs_disk_key *key, u64 bytenr, |
| 3174 | int slot, int level) |
| 3175 | { |
| 3176 | struct extent_buffer *lower; |
| 3177 | int nritems; |
| 3178 | int ret; |
| 3179 | |
| 3180 | BUG_ON(!path->nodes[level]); |
| 3181 | btrfs_assert_tree_locked(path->nodes[level]); |
| 3182 | lower = path->nodes[level]; |
| 3183 | nritems = btrfs_header_nritems(lower); |
| 3184 | BUG_ON(slot > nritems); |
| 3185 | BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root)); |
| 3186 | if (slot != nritems) { |
| 3187 | if (level) |
| 3188 | tree_mod_log_eb_move(root->fs_info, lower, slot + 1, |
| 3189 | slot, nritems - slot); |
| 3190 | memmove_extent_buffer(lower, |
| 3191 | btrfs_node_key_ptr_offset(slot + 1), |
| 3192 | btrfs_node_key_ptr_offset(slot), |
| 3193 | (nritems - slot) * sizeof(struct btrfs_key_ptr)); |
| 3194 | } |
| 3195 | if (level) { |
| 3196 | ret = tree_mod_log_insert_key(root->fs_info, lower, slot, |
| 3197 | MOD_LOG_KEY_ADD); |
| 3198 | BUG_ON(ret < 0); |
| 3199 | } |
| 3200 | btrfs_set_node_key(lower, key, slot); |
| 3201 | btrfs_set_node_blockptr(lower, slot, bytenr); |
| 3202 | WARN_ON(trans->transid == 0); |
| 3203 | btrfs_set_node_ptr_generation(lower, slot, trans->transid); |
| 3204 | btrfs_set_header_nritems(lower, nritems + 1); |
| 3205 | btrfs_mark_buffer_dirty(lower); |
| 3206 | } |
| 3207 | |
| 3208 | /* |
| 3209 | * split the node at the specified level in path in two. |
| 3210 | * The path is corrected to point to the appropriate node after the split |
| 3211 | * |
| 3212 | * Before splitting this tries to make some room in the node by pushing |
| 3213 | * left and right, if either one works, it returns right away. |
| 3214 | * |
| 3215 | * returns 0 on success and < 0 on failure |
| 3216 | */ |
| 3217 | static noinline int split_node(struct btrfs_trans_handle *trans, |
| 3218 | struct btrfs_root *root, |
| 3219 | struct btrfs_path *path, int level) |
| 3220 | { |
| 3221 | struct extent_buffer *c; |
| 3222 | struct extent_buffer *split; |
| 3223 | struct btrfs_disk_key disk_key; |
| 3224 | int mid; |
| 3225 | int ret; |
| 3226 | u32 c_nritems; |
| 3227 | |
| 3228 | c = path->nodes[level]; |
| 3229 | WARN_ON(btrfs_header_generation(c) != trans->transid); |
| 3230 | if (c == root->node) { |
| 3231 | /* |
| 3232 | * trying to split the root, lets make a new one |
| 3233 | * |
| 3234 | * tree mod log: We pass 0 as log_removal parameter to |
| 3235 | * insert_new_root, because that root buffer will be kept as a |
| 3236 | * normal node. We are going to log removal of half of the |
| 3237 | * elements below with tree_mod_log_eb_copy. We're holding a |
| 3238 | * tree lock on the buffer, which is why we cannot race with |
| 3239 | * other tree_mod_log users. |
| 3240 | */ |
| 3241 | ret = insert_new_root(trans, root, path, level + 1, 0); |
| 3242 | if (ret) |
| 3243 | return ret; |
| 3244 | } else { |
| 3245 | ret = push_nodes_for_insert(trans, root, path, level); |
| 3246 | c = path->nodes[level]; |
| 3247 | if (!ret && btrfs_header_nritems(c) < |
| 3248 | BTRFS_NODEPTRS_PER_BLOCK(root) - 3) |
| 3249 | return 0; |
| 3250 | if (ret < 0) |
| 3251 | return ret; |
| 3252 | } |
| 3253 | |
| 3254 | c_nritems = btrfs_header_nritems(c); |
| 3255 | mid = (c_nritems + 1) / 2; |
| 3256 | btrfs_node_key(c, &disk_key, mid); |
| 3257 | |
| 3258 | split = btrfs_alloc_free_block(trans, root, root->nodesize, 0, |
| 3259 | root->root_key.objectid, |
| 3260 | &disk_key, level, c->start, 0); |
| 3261 | if (IS_ERR(split)) |
| 3262 | return PTR_ERR(split); |
| 3263 | |
| 3264 | root_add_used(root, root->nodesize); |
| 3265 | |
| 3266 | memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header)); |
| 3267 | btrfs_set_header_level(split, btrfs_header_level(c)); |
| 3268 | btrfs_set_header_bytenr(split, split->start); |
| 3269 | btrfs_set_header_generation(split, trans->transid); |
| 3270 | btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV); |
| 3271 | btrfs_set_header_owner(split, root->root_key.objectid); |
| 3272 | write_extent_buffer(split, root->fs_info->fsid, |
| 3273 | (unsigned long)btrfs_header_fsid(split), |
| 3274 | BTRFS_FSID_SIZE); |
| 3275 | write_extent_buffer(split, root->fs_info->chunk_tree_uuid, |
| 3276 | (unsigned long)btrfs_header_chunk_tree_uuid(split), |
| 3277 | BTRFS_UUID_SIZE); |
| 3278 | |
| 3279 | tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid); |
| 3280 | copy_extent_buffer(split, c, |
| 3281 | btrfs_node_key_ptr_offset(0), |
| 3282 | btrfs_node_key_ptr_offset(mid), |
| 3283 | (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); |
| 3284 | btrfs_set_header_nritems(split, c_nritems - mid); |
| 3285 | btrfs_set_header_nritems(c, mid); |
| 3286 | ret = 0; |
| 3287 | |
| 3288 | btrfs_mark_buffer_dirty(c); |
| 3289 | btrfs_mark_buffer_dirty(split); |
| 3290 | |
| 3291 | insert_ptr(trans, root, path, &disk_key, split->start, |
| 3292 | path->slots[level + 1] + 1, level + 1); |
| 3293 | |
| 3294 | if (path->slots[level] >= mid) { |
| 3295 | path->slots[level] -= mid; |
| 3296 | btrfs_tree_unlock(c); |
| 3297 | free_extent_buffer(c); |
| 3298 | path->nodes[level] = split; |
| 3299 | path->slots[level + 1] += 1; |
| 3300 | } else { |
| 3301 | btrfs_tree_unlock(split); |
| 3302 | free_extent_buffer(split); |
| 3303 | } |
| 3304 | return ret; |
| 3305 | } |
| 3306 | |
| 3307 | /* |
| 3308 | * how many bytes are required to store the items in a leaf. start |
| 3309 | * and nr indicate which items in the leaf to check. This totals up the |
| 3310 | * space used both by the item structs and the item data |
| 3311 | */ |
| 3312 | static int leaf_space_used(struct extent_buffer *l, int start, int nr) |
| 3313 | { |
| 3314 | struct btrfs_item *start_item; |
| 3315 | struct btrfs_item *end_item; |
| 3316 | struct btrfs_map_token token; |
| 3317 | int data_len; |
| 3318 | int nritems = btrfs_header_nritems(l); |
| 3319 | int end = min(nritems, start + nr) - 1; |
| 3320 | |
| 3321 | if (!nr) |
| 3322 | return 0; |
| 3323 | btrfs_init_map_token(&token); |
| 3324 | start_item = btrfs_item_nr(l, start); |
| 3325 | end_item = btrfs_item_nr(l, end); |
| 3326 | data_len = btrfs_token_item_offset(l, start_item, &token) + |
| 3327 | btrfs_token_item_size(l, start_item, &token); |
| 3328 | data_len = data_len - btrfs_token_item_offset(l, end_item, &token); |
| 3329 | data_len += sizeof(struct btrfs_item) * nr; |
| 3330 | WARN_ON(data_len < 0); |
| 3331 | return data_len; |
| 3332 | } |
| 3333 | |
| 3334 | /* |
| 3335 | * The space between the end of the leaf items and |
| 3336 | * the start of the leaf data. IOW, how much room |
| 3337 | * the leaf has left for both items and data |
| 3338 | */ |
| 3339 | noinline int btrfs_leaf_free_space(struct btrfs_root *root, |
| 3340 | struct extent_buffer *leaf) |
| 3341 | { |
| 3342 | int nritems = btrfs_header_nritems(leaf); |
| 3343 | int ret; |
| 3344 | ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems); |
| 3345 | if (ret < 0) { |
| 3346 | printk(KERN_CRIT "leaf free space ret %d, leaf data size %lu, " |
| 3347 | "used %d nritems %d\n", |
| 3348 | ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root), |
| 3349 | leaf_space_used(leaf, 0, nritems), nritems); |
| 3350 | } |
| 3351 | return ret; |
| 3352 | } |
| 3353 | |
| 3354 | /* |
| 3355 | * min slot controls the lowest index we're willing to push to the |
| 3356 | * right. We'll push up to and including min_slot, but no lower |
| 3357 | */ |
| 3358 | static noinline int __push_leaf_right(struct btrfs_trans_handle *trans, |
| 3359 | struct btrfs_root *root, |
| 3360 | struct btrfs_path *path, |
| 3361 | int data_size, int empty, |
| 3362 | struct extent_buffer *right, |
| 3363 | int free_space, u32 left_nritems, |
| 3364 | u32 min_slot) |
| 3365 | { |
| 3366 | struct extent_buffer *left = path->nodes[0]; |
| 3367 | struct extent_buffer *upper = path->nodes[1]; |
| 3368 | struct btrfs_map_token token; |
| 3369 | struct btrfs_disk_key disk_key; |
| 3370 | int slot; |
| 3371 | u32 i; |
| 3372 | int push_space = 0; |
| 3373 | int push_items = 0; |
| 3374 | struct btrfs_item *item; |
| 3375 | u32 nr; |
| 3376 | u32 right_nritems; |
| 3377 | u32 data_end; |
| 3378 | u32 this_item_size; |
| 3379 | |
| 3380 | btrfs_init_map_token(&token); |
| 3381 | |
| 3382 | if (empty) |
| 3383 | nr = 0; |
| 3384 | else |
| 3385 | nr = max_t(u32, 1, min_slot); |
| 3386 | |
| 3387 | if (path->slots[0] >= left_nritems) |
| 3388 | push_space += data_size; |
| 3389 | |
| 3390 | slot = path->slots[1]; |
| 3391 | i = left_nritems - 1; |
| 3392 | while (i >= nr) { |
| 3393 | item = btrfs_item_nr(left, i); |
| 3394 | |
| 3395 | if (!empty && push_items > 0) { |
| 3396 | if (path->slots[0] > i) |
| 3397 | break; |
| 3398 | if (path->slots[0] == i) { |
| 3399 | int space = btrfs_leaf_free_space(root, left); |
| 3400 | if (space + push_space * 2 > free_space) |
| 3401 | break; |
| 3402 | } |
| 3403 | } |
| 3404 | |
| 3405 | if (path->slots[0] == i) |
| 3406 | push_space += data_size; |
| 3407 | |
| 3408 | this_item_size = btrfs_item_size(left, item); |
| 3409 | if (this_item_size + sizeof(*item) + push_space > free_space) |
| 3410 | break; |
| 3411 | |
| 3412 | push_items++; |
| 3413 | push_space += this_item_size + sizeof(*item); |
| 3414 | if (i == 0) |
| 3415 | break; |
| 3416 | i--; |
| 3417 | } |
| 3418 | |
| 3419 | if (push_items == 0) |
| 3420 | goto out_unlock; |
| 3421 | |
| 3422 | WARN_ON(!empty && push_items == left_nritems); |
| 3423 | |
| 3424 | /* push left to right */ |
| 3425 | right_nritems = btrfs_header_nritems(right); |
| 3426 | |
| 3427 | push_space = btrfs_item_end_nr(left, left_nritems - push_items); |
| 3428 | push_space -= leaf_data_end(root, left); |
| 3429 | |
| 3430 | /* make room in the right data area */ |
| 3431 | data_end = leaf_data_end(root, right); |
| 3432 | memmove_extent_buffer(right, |
| 3433 | btrfs_leaf_data(right) + data_end - push_space, |
| 3434 | btrfs_leaf_data(right) + data_end, |
| 3435 | BTRFS_LEAF_DATA_SIZE(root) - data_end); |
| 3436 | |
| 3437 | /* copy from the left data area */ |
| 3438 | copy_extent_buffer(right, left, btrfs_leaf_data(right) + |
| 3439 | BTRFS_LEAF_DATA_SIZE(root) - push_space, |
| 3440 | btrfs_leaf_data(left) + leaf_data_end(root, left), |
| 3441 | push_space); |
| 3442 | |
| 3443 | memmove_extent_buffer(right, btrfs_item_nr_offset(push_items), |
| 3444 | btrfs_item_nr_offset(0), |
| 3445 | right_nritems * sizeof(struct btrfs_item)); |
| 3446 | |
| 3447 | /* copy the items from left to right */ |
| 3448 | copy_extent_buffer(right, left, btrfs_item_nr_offset(0), |
| 3449 | btrfs_item_nr_offset(left_nritems - push_items), |
| 3450 | push_items * sizeof(struct btrfs_item)); |
| 3451 | |
| 3452 | /* update the item pointers */ |
| 3453 | right_nritems += push_items; |
| 3454 | btrfs_set_header_nritems(right, right_nritems); |
| 3455 | push_space = BTRFS_LEAF_DATA_SIZE(root); |
| 3456 | for (i = 0; i < right_nritems; i++) { |
| 3457 | item = btrfs_item_nr(right, i); |
| 3458 | push_space -= btrfs_token_item_size(right, item, &token); |
| 3459 | btrfs_set_token_item_offset(right, item, push_space, &token); |
| 3460 | } |
| 3461 | |
| 3462 | left_nritems -= push_items; |
| 3463 | btrfs_set_header_nritems(left, left_nritems); |
| 3464 | |
| 3465 | if (left_nritems) |
| 3466 | btrfs_mark_buffer_dirty(left); |
| 3467 | else |
| 3468 | clean_tree_block(trans, root, left); |
| 3469 | |
| 3470 | btrfs_mark_buffer_dirty(right); |
| 3471 | |
| 3472 | btrfs_item_key(right, &disk_key, 0); |
| 3473 | btrfs_set_node_key(upper, &disk_key, slot + 1); |
| 3474 | btrfs_mark_buffer_dirty(upper); |
| 3475 | |
| 3476 | /* then fixup the leaf pointer in the path */ |
| 3477 | if (path->slots[0] >= left_nritems) { |
| 3478 | path->slots[0] -= left_nritems; |
| 3479 | if (btrfs_header_nritems(path->nodes[0]) == 0) |
| 3480 | clean_tree_block(trans, root, path->nodes[0]); |
| 3481 | btrfs_tree_unlock(path->nodes[0]); |
| 3482 | free_extent_buffer(path->nodes[0]); |
| 3483 | path->nodes[0] = right; |
| 3484 | path->slots[1] += 1; |
| 3485 | } else { |
| 3486 | btrfs_tree_unlock(right); |
| 3487 | free_extent_buffer(right); |
| 3488 | } |
| 3489 | return 0; |
| 3490 | |
| 3491 | out_unlock: |
| 3492 | btrfs_tree_unlock(right); |
| 3493 | free_extent_buffer(right); |
| 3494 | return 1; |
| 3495 | } |
| 3496 | |
| 3497 | /* |
| 3498 | * push some data in the path leaf to the right, trying to free up at |
| 3499 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| 3500 | * |
| 3501 | * returns 1 if the push failed because the other node didn't have enough |
| 3502 | * room, 0 if everything worked out and < 0 if there were major errors. |
| 3503 | * |
| 3504 | * this will push starting from min_slot to the end of the leaf. It won't |
| 3505 | * push any slot lower than min_slot |
| 3506 | */ |
| 3507 | static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root |
| 3508 | *root, struct btrfs_path *path, |
| 3509 | int min_data_size, int data_size, |
| 3510 | int empty, u32 min_slot) |
| 3511 | { |
| 3512 | struct extent_buffer *left = path->nodes[0]; |
| 3513 | struct extent_buffer *right; |
| 3514 | struct extent_buffer *upper; |
| 3515 | int slot; |
| 3516 | int free_space; |
| 3517 | u32 left_nritems; |
| 3518 | int ret; |
| 3519 | |
| 3520 | if (!path->nodes[1]) |
| 3521 | return 1; |
| 3522 | |
| 3523 | slot = path->slots[1]; |
| 3524 | upper = path->nodes[1]; |
| 3525 | if (slot >= btrfs_header_nritems(upper) - 1) |
| 3526 | return 1; |
| 3527 | |
| 3528 | btrfs_assert_tree_locked(path->nodes[1]); |
| 3529 | |
| 3530 | right = read_node_slot(root, upper, slot + 1); |
| 3531 | if (right == NULL) |
| 3532 | return 1; |
| 3533 | |
| 3534 | btrfs_tree_lock(right); |
| 3535 | btrfs_set_lock_blocking(right); |
| 3536 | |
| 3537 | free_space = btrfs_leaf_free_space(root, right); |
| 3538 | if (free_space < data_size) |
| 3539 | goto out_unlock; |
| 3540 | |
| 3541 | /* cow and double check */ |
| 3542 | ret = btrfs_cow_block(trans, root, right, upper, |
| 3543 | slot + 1, &right); |
| 3544 | if (ret) |
| 3545 | goto out_unlock; |
| 3546 | |
| 3547 | free_space = btrfs_leaf_free_space(root, right); |
| 3548 | if (free_space < data_size) |
| 3549 | goto out_unlock; |
| 3550 | |
| 3551 | left_nritems = btrfs_header_nritems(left); |
| 3552 | if (left_nritems == 0) |
| 3553 | goto out_unlock; |
| 3554 | |
| 3555 | return __push_leaf_right(trans, root, path, min_data_size, empty, |
| 3556 | right, free_space, left_nritems, min_slot); |
| 3557 | out_unlock: |
| 3558 | btrfs_tree_unlock(right); |
| 3559 | free_extent_buffer(right); |
| 3560 | return 1; |
| 3561 | } |
| 3562 | |
| 3563 | /* |
| 3564 | * push some data in the path leaf to the left, trying to free up at |
| 3565 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| 3566 | * |
| 3567 | * max_slot can put a limit on how far into the leaf we'll push items. The |
| 3568 | * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the |
| 3569 | * items |
| 3570 | */ |
| 3571 | static noinline int __push_leaf_left(struct btrfs_trans_handle *trans, |
| 3572 | struct btrfs_root *root, |
| 3573 | struct btrfs_path *path, int data_size, |
| 3574 | int empty, struct extent_buffer *left, |
| 3575 | int free_space, u32 right_nritems, |
| 3576 | u32 max_slot) |
| 3577 | { |
| 3578 | struct btrfs_disk_key disk_key; |
| 3579 | struct extent_buffer *right = path->nodes[0]; |
| 3580 | int i; |
| 3581 | int push_space = 0; |
| 3582 | int push_items = 0; |
| 3583 | struct btrfs_item *item; |
| 3584 | u32 old_left_nritems; |
| 3585 | u32 nr; |
| 3586 | int ret = 0; |
| 3587 | u32 this_item_size; |
| 3588 | u32 old_left_item_size; |
| 3589 | struct btrfs_map_token token; |
| 3590 | |
| 3591 | btrfs_init_map_token(&token); |
| 3592 | |
| 3593 | if (empty) |
| 3594 | nr = min(right_nritems, max_slot); |
| 3595 | else |
| 3596 | nr = min(right_nritems - 1, max_slot); |
| 3597 | |
| 3598 | for (i = 0; i < nr; i++) { |
| 3599 | item = btrfs_item_nr(right, i); |
| 3600 | |
| 3601 | if (!empty && push_items > 0) { |
| 3602 | if (path->slots[0] < i) |
| 3603 | break; |
| 3604 | if (path->slots[0] == i) { |
| 3605 | int space = btrfs_leaf_free_space(root, right); |
| 3606 | if (space + push_space * 2 > free_space) |
| 3607 | break; |
| 3608 | } |
| 3609 | } |
| 3610 | |
| 3611 | if (path->slots[0] == i) |
| 3612 | push_space += data_size; |
| 3613 | |
| 3614 | this_item_size = btrfs_item_size(right, item); |
| 3615 | if (this_item_size + sizeof(*item) + push_space > free_space) |
| 3616 | break; |
| 3617 | |
| 3618 | push_items++; |
| 3619 | push_space += this_item_size + sizeof(*item); |
| 3620 | } |
| 3621 | |
| 3622 | if (push_items == 0) { |
| 3623 | ret = 1; |
| 3624 | goto out; |
| 3625 | } |
| 3626 | if (!empty && push_items == btrfs_header_nritems(right)) |
| 3627 | WARN_ON(1); |
| 3628 | |
| 3629 | /* push data from right to left */ |
| 3630 | copy_extent_buffer(left, right, |
| 3631 | btrfs_item_nr_offset(btrfs_header_nritems(left)), |
| 3632 | btrfs_item_nr_offset(0), |
| 3633 | push_items * sizeof(struct btrfs_item)); |
| 3634 | |
| 3635 | push_space = BTRFS_LEAF_DATA_SIZE(root) - |
| 3636 | btrfs_item_offset_nr(right, push_items - 1); |
| 3637 | |
| 3638 | copy_extent_buffer(left, right, btrfs_leaf_data(left) + |
| 3639 | leaf_data_end(root, left) - push_space, |
| 3640 | btrfs_leaf_data(right) + |
| 3641 | btrfs_item_offset_nr(right, push_items - 1), |
| 3642 | push_space); |
| 3643 | old_left_nritems = btrfs_header_nritems(left); |
| 3644 | BUG_ON(old_left_nritems <= 0); |
| 3645 | |
| 3646 | old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1); |
| 3647 | for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { |
| 3648 | u32 ioff; |
| 3649 | |
| 3650 | item = btrfs_item_nr(left, i); |
| 3651 | |
| 3652 | ioff = btrfs_token_item_offset(left, item, &token); |
| 3653 | btrfs_set_token_item_offset(left, item, |
| 3654 | ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size), |
| 3655 | &token); |
| 3656 | } |
| 3657 | btrfs_set_header_nritems(left, old_left_nritems + push_items); |
| 3658 | |
| 3659 | /* fixup right node */ |
| 3660 | if (push_items > right_nritems) |
| 3661 | WARN(1, KERN_CRIT "push items %d nr %u\n", push_items, |
| 3662 | right_nritems); |
| 3663 | |
| 3664 | if (push_items < right_nritems) { |
| 3665 | push_space = btrfs_item_offset_nr(right, push_items - 1) - |
| 3666 | leaf_data_end(root, right); |
| 3667 | memmove_extent_buffer(right, btrfs_leaf_data(right) + |
| 3668 | BTRFS_LEAF_DATA_SIZE(root) - push_space, |
| 3669 | btrfs_leaf_data(right) + |
| 3670 | leaf_data_end(root, right), push_space); |
| 3671 | |
| 3672 | memmove_extent_buffer(right, btrfs_item_nr_offset(0), |
| 3673 | btrfs_item_nr_offset(push_items), |
| 3674 | (btrfs_header_nritems(right) - push_items) * |
| 3675 | sizeof(struct btrfs_item)); |
| 3676 | } |
| 3677 | right_nritems -= push_items; |
| 3678 | btrfs_set_header_nritems(right, right_nritems); |
| 3679 | push_space = BTRFS_LEAF_DATA_SIZE(root); |
| 3680 | for (i = 0; i < right_nritems; i++) { |
| 3681 | item = btrfs_item_nr(right, i); |
| 3682 | |
| 3683 | push_space = push_space - btrfs_token_item_size(right, |
| 3684 | item, &token); |
| 3685 | btrfs_set_token_item_offset(right, item, push_space, &token); |
| 3686 | } |
| 3687 | |
| 3688 | btrfs_mark_buffer_dirty(left); |
| 3689 | if (right_nritems) |
| 3690 | btrfs_mark_buffer_dirty(right); |
| 3691 | else |
| 3692 | clean_tree_block(trans, root, right); |
| 3693 | |
| 3694 | btrfs_item_key(right, &disk_key, 0); |
| 3695 | fixup_low_keys(trans, root, path, &disk_key, 1); |
| 3696 | |
| 3697 | /* then fixup the leaf pointer in the path */ |
| 3698 | if (path->slots[0] < push_items) { |
| 3699 | path->slots[0] += old_left_nritems; |
| 3700 | btrfs_tree_unlock(path->nodes[0]); |
| 3701 | free_extent_buffer(path->nodes[0]); |
| 3702 | path->nodes[0] = left; |
| 3703 | path->slots[1] -= 1; |
| 3704 | } else { |
| 3705 | btrfs_tree_unlock(left); |
| 3706 | free_extent_buffer(left); |
| 3707 | path->slots[0] -= push_items; |
| 3708 | } |
| 3709 | BUG_ON(path->slots[0] < 0); |
| 3710 | return ret; |
| 3711 | out: |
| 3712 | btrfs_tree_unlock(left); |
| 3713 | free_extent_buffer(left); |
| 3714 | return ret; |
| 3715 | } |
| 3716 | |
| 3717 | /* |
| 3718 | * push some data in the path leaf to the left, trying to free up at |
| 3719 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| 3720 | * |
| 3721 | * max_slot can put a limit on how far into the leaf we'll push items. The |
| 3722 | * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the |
| 3723 | * items |
| 3724 | */ |
| 3725 | static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root |
| 3726 | *root, struct btrfs_path *path, int min_data_size, |
| 3727 | int data_size, int empty, u32 max_slot) |
| 3728 | { |
| 3729 | struct extent_buffer *right = path->nodes[0]; |
| 3730 | struct extent_buffer *left; |
| 3731 | int slot; |
| 3732 | int free_space; |
| 3733 | u32 right_nritems; |
| 3734 | int ret = 0; |
| 3735 | |
| 3736 | slot = path->slots[1]; |
| 3737 | if (slot == 0) |
| 3738 | return 1; |
| 3739 | if (!path->nodes[1]) |
| 3740 | return 1; |
| 3741 | |
| 3742 | right_nritems = btrfs_header_nritems(right); |
| 3743 | if (right_nritems == 0) |
| 3744 | return 1; |
| 3745 | |
| 3746 | btrfs_assert_tree_locked(path->nodes[1]); |
| 3747 | |
| 3748 | left = read_node_slot(root, path->nodes[1], slot - 1); |
| 3749 | if (left == NULL) |
| 3750 | return 1; |
| 3751 | |
| 3752 | btrfs_tree_lock(left); |
| 3753 | btrfs_set_lock_blocking(left); |
| 3754 | |
| 3755 | free_space = btrfs_leaf_free_space(root, left); |
| 3756 | if (free_space < data_size) { |
| 3757 | ret = 1; |
| 3758 | goto out; |
| 3759 | } |
| 3760 | |
| 3761 | /* cow and double check */ |
| 3762 | ret = btrfs_cow_block(trans, root, left, |
| 3763 | path->nodes[1], slot - 1, &left); |
| 3764 | if (ret) { |
| 3765 | /* we hit -ENOSPC, but it isn't fatal here */ |
| 3766 | if (ret == -ENOSPC) |
| 3767 | ret = 1; |
| 3768 | goto out; |
| 3769 | } |
| 3770 | |
| 3771 | free_space = btrfs_leaf_free_space(root, left); |
| 3772 | if (free_space < data_size) { |
| 3773 | ret = 1; |
| 3774 | goto out; |
| 3775 | } |
| 3776 | |
| 3777 | return __push_leaf_left(trans, root, path, min_data_size, |
| 3778 | empty, left, free_space, right_nritems, |
| 3779 | max_slot); |
| 3780 | out: |
| 3781 | btrfs_tree_unlock(left); |
| 3782 | free_extent_buffer(left); |
| 3783 | return ret; |
| 3784 | } |
| 3785 | |
| 3786 | /* |
| 3787 | * split the path's leaf in two, making sure there is at least data_size |
| 3788 | * available for the resulting leaf level of the path. |
| 3789 | */ |
| 3790 | static noinline void copy_for_split(struct btrfs_trans_handle *trans, |
| 3791 | struct btrfs_root *root, |
| 3792 | struct btrfs_path *path, |
| 3793 | struct extent_buffer *l, |
| 3794 | struct extent_buffer *right, |
| 3795 | int slot, int mid, int nritems) |
| 3796 | { |
| 3797 | int data_copy_size; |
| 3798 | int rt_data_off; |
| 3799 | int i; |
| 3800 | struct btrfs_disk_key disk_key; |
| 3801 | struct btrfs_map_token token; |
| 3802 | |
| 3803 | btrfs_init_map_token(&token); |
| 3804 | |
| 3805 | nritems = nritems - mid; |
| 3806 | btrfs_set_header_nritems(right, nritems); |
| 3807 | data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l); |
| 3808 | |
| 3809 | copy_extent_buffer(right, l, btrfs_item_nr_offset(0), |
| 3810 | btrfs_item_nr_offset(mid), |
| 3811 | nritems * sizeof(struct btrfs_item)); |
| 3812 | |
| 3813 | copy_extent_buffer(right, l, |
| 3814 | btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) - |
| 3815 | data_copy_size, btrfs_leaf_data(l) + |
| 3816 | leaf_data_end(root, l), data_copy_size); |
| 3817 | |
| 3818 | rt_data_off = BTRFS_LEAF_DATA_SIZE(root) - |
| 3819 | btrfs_item_end_nr(l, mid); |
| 3820 | |
| 3821 | for (i = 0; i < nritems; i++) { |
| 3822 | struct btrfs_item *item = btrfs_item_nr(right, i); |
| 3823 | u32 ioff; |
| 3824 | |
| 3825 | ioff = btrfs_token_item_offset(right, item, &token); |
| 3826 | btrfs_set_token_item_offset(right, item, |
| 3827 | ioff + rt_data_off, &token); |
| 3828 | } |
| 3829 | |
| 3830 | btrfs_set_header_nritems(l, mid); |
| 3831 | btrfs_item_key(right, &disk_key, 0); |
| 3832 | insert_ptr(trans, root, path, &disk_key, right->start, |
| 3833 | path->slots[1] + 1, 1); |
| 3834 | |
| 3835 | btrfs_mark_buffer_dirty(right); |
| 3836 | btrfs_mark_buffer_dirty(l); |
| 3837 | BUG_ON(path->slots[0] != slot); |
| 3838 | |
| 3839 | if (mid <= slot) { |
| 3840 | btrfs_tree_unlock(path->nodes[0]); |
| 3841 | free_extent_buffer(path->nodes[0]); |
| 3842 | path->nodes[0] = right; |
| 3843 | path->slots[0] -= mid; |
| 3844 | path->slots[1] += 1; |
| 3845 | } else { |
| 3846 | btrfs_tree_unlock(right); |
| 3847 | free_extent_buffer(right); |
| 3848 | } |
| 3849 | |
| 3850 | BUG_ON(path->slots[0] < 0); |
| 3851 | } |
| 3852 | |
| 3853 | /* |
| 3854 | * double splits happen when we need to insert a big item in the middle |
| 3855 | * of a leaf. A double split can leave us with 3 mostly empty leaves: |
| 3856 | * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ] |
| 3857 | * A B C |
| 3858 | * |
| 3859 | * We avoid this by trying to push the items on either side of our target |
| 3860 | * into the adjacent leaves. If all goes well we can avoid the double split |
| 3861 | * completely. |
| 3862 | */ |
| 3863 | static noinline int push_for_double_split(struct btrfs_trans_handle *trans, |
| 3864 | struct btrfs_root *root, |
| 3865 | struct btrfs_path *path, |
| 3866 | int data_size) |
| 3867 | { |
| 3868 | int ret; |
| 3869 | int progress = 0; |
| 3870 | int slot; |
| 3871 | u32 nritems; |
| 3872 | |
| 3873 | slot = path->slots[0]; |
| 3874 | |
| 3875 | /* |
| 3876 | * try to push all the items after our slot into the |
| 3877 | * right leaf |
| 3878 | */ |
| 3879 | ret = push_leaf_right(trans, root, path, 1, data_size, 0, slot); |
| 3880 | if (ret < 0) |
| 3881 | return ret; |
| 3882 | |
| 3883 | if (ret == 0) |
| 3884 | progress++; |
| 3885 | |
| 3886 | nritems = btrfs_header_nritems(path->nodes[0]); |
| 3887 | /* |
| 3888 | * our goal is to get our slot at the start or end of a leaf. If |
| 3889 | * we've done so we're done |
| 3890 | */ |
| 3891 | if (path->slots[0] == 0 || path->slots[0] == nritems) |
| 3892 | return 0; |
| 3893 | |
| 3894 | if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size) |
| 3895 | return 0; |
| 3896 | |
| 3897 | /* try to push all the items before our slot into the next leaf */ |
| 3898 | slot = path->slots[0]; |
| 3899 | ret = push_leaf_left(trans, root, path, 1, data_size, 0, slot); |
| 3900 | if (ret < 0) |
| 3901 | return ret; |
| 3902 | |
| 3903 | if (ret == 0) |
| 3904 | progress++; |
| 3905 | |
| 3906 | if (progress) |
| 3907 | return 0; |
| 3908 | return 1; |
| 3909 | } |
| 3910 | |
| 3911 | /* |
| 3912 | * split the path's leaf in two, making sure there is at least data_size |
| 3913 | * available for the resulting leaf level of the path. |
| 3914 | * |
| 3915 | * returns 0 if all went well and < 0 on failure. |
| 3916 | */ |
| 3917 | static noinline int split_leaf(struct btrfs_trans_handle *trans, |
| 3918 | struct btrfs_root *root, |
| 3919 | struct btrfs_key *ins_key, |
| 3920 | struct btrfs_path *path, int data_size, |
| 3921 | int extend) |
| 3922 | { |
| 3923 | struct btrfs_disk_key disk_key; |
| 3924 | struct extent_buffer *l; |
| 3925 | u32 nritems; |
| 3926 | int mid; |
| 3927 | int slot; |
| 3928 | struct extent_buffer *right; |
| 3929 | int ret = 0; |
| 3930 | int wret; |
| 3931 | int split; |
| 3932 | int num_doubles = 0; |
| 3933 | int tried_avoid_double = 0; |
| 3934 | |
| 3935 | l = path->nodes[0]; |
| 3936 | slot = path->slots[0]; |
| 3937 | if (extend && data_size + btrfs_item_size_nr(l, slot) + |
| 3938 | sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root)) |
| 3939 | return -EOVERFLOW; |
| 3940 | |
| 3941 | /* first try to make some room by pushing left and right */ |
| 3942 | if (data_size) { |
| 3943 | wret = push_leaf_right(trans, root, path, data_size, |
| 3944 | data_size, 0, 0); |
| 3945 | if (wret < 0) |
| 3946 | return wret; |
| 3947 | if (wret) { |
| 3948 | wret = push_leaf_left(trans, root, path, data_size, |
| 3949 | data_size, 0, (u32)-1); |
| 3950 | if (wret < 0) |
| 3951 | return wret; |
| 3952 | } |
| 3953 | l = path->nodes[0]; |
| 3954 | |
| 3955 | /* did the pushes work? */ |
| 3956 | if (btrfs_leaf_free_space(root, l) >= data_size) |
| 3957 | return 0; |
| 3958 | } |
| 3959 | |
| 3960 | if (!path->nodes[1]) { |
| 3961 | ret = insert_new_root(trans, root, path, 1, 1); |
| 3962 | if (ret) |
| 3963 | return ret; |
| 3964 | } |
| 3965 | again: |
| 3966 | split = 1; |
| 3967 | l = path->nodes[0]; |
| 3968 | slot = path->slots[0]; |
| 3969 | nritems = btrfs_header_nritems(l); |
| 3970 | mid = (nritems + 1) / 2; |
| 3971 | |
| 3972 | if (mid <= slot) { |
| 3973 | if (nritems == 1 || |
| 3974 | leaf_space_used(l, mid, nritems - mid) + data_size > |
| 3975 | BTRFS_LEAF_DATA_SIZE(root)) { |
| 3976 | if (slot >= nritems) { |
| 3977 | split = 0; |
| 3978 | } else { |
| 3979 | mid = slot; |
| 3980 | if (mid != nritems && |
| 3981 | leaf_space_used(l, mid, nritems - mid) + |
| 3982 | data_size > BTRFS_LEAF_DATA_SIZE(root)) { |
| 3983 | if (data_size && !tried_avoid_double) |
| 3984 | goto push_for_double; |
| 3985 | split = 2; |
| 3986 | } |
| 3987 | } |
| 3988 | } |
| 3989 | } else { |
| 3990 | if (leaf_space_used(l, 0, mid) + data_size > |
| 3991 | BTRFS_LEAF_DATA_SIZE(root)) { |
| 3992 | if (!extend && data_size && slot == 0) { |
| 3993 | split = 0; |
| 3994 | } else if ((extend || !data_size) && slot == 0) { |
| 3995 | mid = 1; |
| 3996 | } else { |
| 3997 | mid = slot; |
| 3998 | if (mid != nritems && |
| 3999 | leaf_space_used(l, mid, nritems - mid) + |
| 4000 | data_size > BTRFS_LEAF_DATA_SIZE(root)) { |
| 4001 | if (data_size && !tried_avoid_double) |
| 4002 | goto push_for_double; |
| 4003 | split = 2 ; |
| 4004 | } |
| 4005 | } |
| 4006 | } |
| 4007 | } |
| 4008 | |
| 4009 | if (split == 0) |
| 4010 | btrfs_cpu_key_to_disk(&disk_key, ins_key); |
| 4011 | else |
| 4012 | btrfs_item_key(l, &disk_key, mid); |
| 4013 | |
| 4014 | right = btrfs_alloc_free_block(trans, root, root->leafsize, 0, |
| 4015 | root->root_key.objectid, |
| 4016 | &disk_key, 0, l->start, 0); |
| 4017 | if (IS_ERR(right)) |
| 4018 | return PTR_ERR(right); |
| 4019 | |
| 4020 | root_add_used(root, root->leafsize); |
| 4021 | |
| 4022 | memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header)); |
| 4023 | btrfs_set_header_bytenr(right, right->start); |
| 4024 | btrfs_set_header_generation(right, trans->transid); |
| 4025 | btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV); |
| 4026 | btrfs_set_header_owner(right, root->root_key.objectid); |
| 4027 | btrfs_set_header_level(right, 0); |
| 4028 | write_extent_buffer(right, root->fs_info->fsid, |
| 4029 | (unsigned long)btrfs_header_fsid(right), |
| 4030 | BTRFS_FSID_SIZE); |
| 4031 | |
| 4032 | write_extent_buffer(right, root->fs_info->chunk_tree_uuid, |
| 4033 | (unsigned long)btrfs_header_chunk_tree_uuid(right), |
| 4034 | BTRFS_UUID_SIZE); |
| 4035 | |
| 4036 | if (split == 0) { |
| 4037 | if (mid <= slot) { |
| 4038 | btrfs_set_header_nritems(right, 0); |
| 4039 | insert_ptr(trans, root, path, &disk_key, right->start, |
| 4040 | path->slots[1] + 1, 1); |
| 4041 | btrfs_tree_unlock(path->nodes[0]); |
| 4042 | free_extent_buffer(path->nodes[0]); |
| 4043 | path->nodes[0] = right; |
| 4044 | path->slots[0] = 0; |
| 4045 | path->slots[1] += 1; |
| 4046 | } else { |
| 4047 | btrfs_set_header_nritems(right, 0); |
| 4048 | insert_ptr(trans, root, path, &disk_key, right->start, |
| 4049 | path->slots[1], 1); |
| 4050 | btrfs_tree_unlock(path->nodes[0]); |
| 4051 | free_extent_buffer(path->nodes[0]); |
| 4052 | path->nodes[0] = right; |
| 4053 | path->slots[0] = 0; |
| 4054 | if (path->slots[1] == 0) |
| 4055 | fixup_low_keys(trans, root, path, |
| 4056 | &disk_key, 1); |
| 4057 | } |
| 4058 | btrfs_mark_buffer_dirty(right); |
| 4059 | return ret; |
| 4060 | } |
| 4061 | |
| 4062 | copy_for_split(trans, root, path, l, right, slot, mid, nritems); |
| 4063 | |
| 4064 | if (split == 2) { |
| 4065 | BUG_ON(num_doubles != 0); |
| 4066 | num_doubles++; |
| 4067 | goto again; |
| 4068 | } |
| 4069 | |
| 4070 | return 0; |
| 4071 | |
| 4072 | push_for_double: |
| 4073 | push_for_double_split(trans, root, path, data_size); |
| 4074 | tried_avoid_double = 1; |
| 4075 | if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size) |
| 4076 | return 0; |
| 4077 | goto again; |
| 4078 | } |
| 4079 | |
| 4080 | static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, |
| 4081 | struct btrfs_root *root, |
| 4082 | struct btrfs_path *path, int ins_len) |
| 4083 | { |
| 4084 | struct btrfs_key key; |
| 4085 | struct extent_buffer *leaf; |
| 4086 | struct btrfs_file_extent_item *fi; |
| 4087 | u64 extent_len = 0; |
| 4088 | u32 item_size; |
| 4089 | int ret; |
| 4090 | |
| 4091 | leaf = path->nodes[0]; |
| 4092 | btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); |
| 4093 | |
| 4094 | BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY && |
| 4095 | key.type != BTRFS_EXTENT_CSUM_KEY); |
| 4096 | |
| 4097 | if (btrfs_leaf_free_space(root, leaf) >= ins_len) |
| 4098 | return 0; |
| 4099 | |
| 4100 | item_size = btrfs_item_size_nr(leaf, path->slots[0]); |
| 4101 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
| 4102 | fi = btrfs_item_ptr(leaf, path->slots[0], |
| 4103 | struct btrfs_file_extent_item); |
| 4104 | extent_len = btrfs_file_extent_num_bytes(leaf, fi); |
| 4105 | } |
| 4106 | btrfs_release_path(path); |
| 4107 | |
| 4108 | path->keep_locks = 1; |
| 4109 | path->search_for_split = 1; |
| 4110 | ret = btrfs_search_slot(trans, root, &key, path, 0, 1); |
| 4111 | path->search_for_split = 0; |
| 4112 | if (ret < 0) |
| 4113 | goto err; |
| 4114 | |
| 4115 | ret = -EAGAIN; |
| 4116 | leaf = path->nodes[0]; |
| 4117 | /* if our item isn't there or got smaller, return now */ |
| 4118 | if (ret > 0 || item_size != btrfs_item_size_nr(leaf, path->slots[0])) |
| 4119 | goto err; |
| 4120 | |
| 4121 | /* the leaf has changed, it now has room. return now */ |
| 4122 | if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len) |
| 4123 | goto err; |
| 4124 | |
| 4125 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
| 4126 | fi = btrfs_item_ptr(leaf, path->slots[0], |
| 4127 | struct btrfs_file_extent_item); |
| 4128 | if (extent_len != btrfs_file_extent_num_bytes(leaf, fi)) |
| 4129 | goto err; |
| 4130 | } |
| 4131 | |
| 4132 | btrfs_set_path_blocking(path); |
| 4133 | ret = split_leaf(trans, root, &key, path, ins_len, 1); |
| 4134 | if (ret) |
| 4135 | goto err; |
| 4136 | |
| 4137 | path->keep_locks = 0; |
| 4138 | btrfs_unlock_up_safe(path, 1); |
| 4139 | return 0; |
| 4140 | err: |
| 4141 | path->keep_locks = 0; |
| 4142 | return ret; |
| 4143 | } |
| 4144 | |
| 4145 | static noinline int split_item(struct btrfs_trans_handle *trans, |
| 4146 | struct btrfs_root *root, |
| 4147 | struct btrfs_path *path, |
| 4148 | struct btrfs_key *new_key, |
| 4149 | unsigned long split_offset) |
| 4150 | { |
| 4151 | struct extent_buffer *leaf; |
| 4152 | struct btrfs_item *item; |
| 4153 | struct btrfs_item *new_item; |
| 4154 | int slot; |
| 4155 | char *buf; |
| 4156 | u32 nritems; |
| 4157 | u32 item_size; |
| 4158 | u32 orig_offset; |
| 4159 | struct btrfs_disk_key disk_key; |
| 4160 | |
| 4161 | leaf = path->nodes[0]; |
| 4162 | BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item)); |
| 4163 | |
| 4164 | btrfs_set_path_blocking(path); |
| 4165 | |
| 4166 | item = btrfs_item_nr(leaf, path->slots[0]); |
| 4167 | orig_offset = btrfs_item_offset(leaf, item); |
| 4168 | item_size = btrfs_item_size(leaf, item); |
| 4169 | |
| 4170 | buf = kmalloc(item_size, GFP_NOFS); |
| 4171 | if (!buf) |
| 4172 | return -ENOMEM; |
| 4173 | |
| 4174 | read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, |
| 4175 | path->slots[0]), item_size); |
| 4176 | |
| 4177 | slot = path->slots[0] + 1; |
| 4178 | nritems = btrfs_header_nritems(leaf); |
| 4179 | if (slot != nritems) { |
| 4180 | /* shift the items */ |
| 4181 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1), |
| 4182 | btrfs_item_nr_offset(slot), |
| 4183 | (nritems - slot) * sizeof(struct btrfs_item)); |
| 4184 | } |
| 4185 | |
| 4186 | btrfs_cpu_key_to_disk(&disk_key, new_key); |
| 4187 | btrfs_set_item_key(leaf, &disk_key, slot); |
| 4188 | |
| 4189 | new_item = btrfs_item_nr(leaf, slot); |
| 4190 | |
| 4191 | btrfs_set_item_offset(leaf, new_item, orig_offset); |
| 4192 | btrfs_set_item_size(leaf, new_item, item_size - split_offset); |
| 4193 | |
| 4194 | btrfs_set_item_offset(leaf, item, |
| 4195 | orig_offset + item_size - split_offset); |
| 4196 | btrfs_set_item_size(leaf, item, split_offset); |
| 4197 | |
| 4198 | btrfs_set_header_nritems(leaf, nritems + 1); |
| 4199 | |
| 4200 | /* write the data for the start of the original item */ |
| 4201 | write_extent_buffer(leaf, buf, |
| 4202 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
| 4203 | split_offset); |
| 4204 | |
| 4205 | /* write the data for the new item */ |
| 4206 | write_extent_buffer(leaf, buf + split_offset, |
| 4207 | btrfs_item_ptr_offset(leaf, slot), |
| 4208 | item_size - split_offset); |
| 4209 | btrfs_mark_buffer_dirty(leaf); |
| 4210 | |
| 4211 | BUG_ON(btrfs_leaf_free_space(root, leaf) < 0); |
| 4212 | kfree(buf); |
| 4213 | return 0; |
| 4214 | } |
| 4215 | |
| 4216 | /* |
| 4217 | * This function splits a single item into two items, |
| 4218 | * giving 'new_key' to the new item and splitting the |
| 4219 | * old one at split_offset (from the start of the item). |
| 4220 | * |
| 4221 | * The path may be released by this operation. After |
| 4222 | * the split, the path is pointing to the old item. The |
| 4223 | * new item is going to be in the same node as the old one. |
| 4224 | * |
| 4225 | * Note, the item being split must be smaller enough to live alone on |
| 4226 | * a tree block with room for one extra struct btrfs_item |
| 4227 | * |
| 4228 | * This allows us to split the item in place, keeping a lock on the |
| 4229 | * leaf the entire time. |
| 4230 | */ |
| 4231 | int btrfs_split_item(struct btrfs_trans_handle *trans, |
| 4232 | struct btrfs_root *root, |
| 4233 | struct btrfs_path *path, |
| 4234 | struct btrfs_key *new_key, |
| 4235 | unsigned long split_offset) |
| 4236 | { |
| 4237 | int ret; |
| 4238 | ret = setup_leaf_for_split(trans, root, path, |
| 4239 | sizeof(struct btrfs_item)); |
| 4240 | if (ret) |
| 4241 | return ret; |
| 4242 | |
| 4243 | ret = split_item(trans, root, path, new_key, split_offset); |
| 4244 | return ret; |
| 4245 | } |
| 4246 | |
| 4247 | /* |
| 4248 | * This function duplicate a item, giving 'new_key' to the new item. |
| 4249 | * It guarantees both items live in the same tree leaf and the new item |
| 4250 | * is contiguous with the original item. |
| 4251 | * |
| 4252 | * This allows us to split file extent in place, keeping a lock on the |
| 4253 | * leaf the entire time. |
| 4254 | */ |
| 4255 | int btrfs_duplicate_item(struct btrfs_trans_handle *trans, |
| 4256 | struct btrfs_root *root, |
| 4257 | struct btrfs_path *path, |
| 4258 | struct btrfs_key *new_key) |
| 4259 | { |
| 4260 | struct extent_buffer *leaf; |
| 4261 | int ret; |
| 4262 | u32 item_size; |
| 4263 | |
| 4264 | leaf = path->nodes[0]; |
| 4265 | item_size = btrfs_item_size_nr(leaf, path->slots[0]); |
| 4266 | ret = setup_leaf_for_split(trans, root, path, |
| 4267 | item_size + sizeof(struct btrfs_item)); |
| 4268 | if (ret) |
| 4269 | return ret; |
| 4270 | |
| 4271 | path->slots[0]++; |
| 4272 | setup_items_for_insert(trans, root, path, new_key, &item_size, |
| 4273 | item_size, item_size + |
| 4274 | sizeof(struct btrfs_item), 1); |
| 4275 | leaf = path->nodes[0]; |
| 4276 | memcpy_extent_buffer(leaf, |
| 4277 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
| 4278 | btrfs_item_ptr_offset(leaf, path->slots[0] - 1), |
| 4279 | item_size); |
| 4280 | return 0; |
| 4281 | } |
| 4282 | |
| 4283 | /* |
| 4284 | * make the item pointed to by the path smaller. new_size indicates |
| 4285 | * how small to make it, and from_end tells us if we just chop bytes |
| 4286 | * off the end of the item or if we shift the item to chop bytes off |
| 4287 | * the front. |
| 4288 | */ |
| 4289 | void btrfs_truncate_item(struct btrfs_trans_handle *trans, |
| 4290 | struct btrfs_root *root, |
| 4291 | struct btrfs_path *path, |
| 4292 | u32 new_size, int from_end) |
| 4293 | { |
| 4294 | int slot; |
| 4295 | struct extent_buffer *leaf; |
| 4296 | struct btrfs_item *item; |
| 4297 | u32 nritems; |
| 4298 | unsigned int data_end; |
| 4299 | unsigned int old_data_start; |
| 4300 | unsigned int old_size; |
| 4301 | unsigned int size_diff; |
| 4302 | int i; |
| 4303 | struct btrfs_map_token token; |
| 4304 | |
| 4305 | btrfs_init_map_token(&token); |
| 4306 | |
| 4307 | leaf = path->nodes[0]; |
| 4308 | slot = path->slots[0]; |
| 4309 | |
| 4310 | old_size = btrfs_item_size_nr(leaf, slot); |
| 4311 | if (old_size == new_size) |
| 4312 | return; |
| 4313 | |
| 4314 | nritems = btrfs_header_nritems(leaf); |
| 4315 | data_end = leaf_data_end(root, leaf); |
| 4316 | |
| 4317 | old_data_start = btrfs_item_offset_nr(leaf, slot); |
| 4318 | |
| 4319 | size_diff = old_size - new_size; |
| 4320 | |
| 4321 | BUG_ON(slot < 0); |
| 4322 | BUG_ON(slot >= nritems); |
| 4323 | |
| 4324 | /* |
| 4325 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
| 4326 | */ |
| 4327 | /* first correct the data pointers */ |
| 4328 | for (i = slot; i < nritems; i++) { |
| 4329 | u32 ioff; |
| 4330 | item = btrfs_item_nr(leaf, i); |
| 4331 | |
| 4332 | ioff = btrfs_token_item_offset(leaf, item, &token); |
| 4333 | btrfs_set_token_item_offset(leaf, item, |
| 4334 | ioff + size_diff, &token); |
| 4335 | } |
| 4336 | |
| 4337 | /* shift the data */ |
| 4338 | if (from_end) { |
| 4339 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
| 4340 | data_end + size_diff, btrfs_leaf_data(leaf) + |
| 4341 | data_end, old_data_start + new_size - data_end); |
| 4342 | } else { |
| 4343 | struct btrfs_disk_key disk_key; |
| 4344 | u64 offset; |
| 4345 | |
| 4346 | btrfs_item_key(leaf, &disk_key, slot); |
| 4347 | |
| 4348 | if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) { |
| 4349 | unsigned long ptr; |
| 4350 | struct btrfs_file_extent_item *fi; |
| 4351 | |
| 4352 | fi = btrfs_item_ptr(leaf, slot, |
| 4353 | struct btrfs_file_extent_item); |
| 4354 | fi = (struct btrfs_file_extent_item *)( |
| 4355 | (unsigned long)fi - size_diff); |
| 4356 | |
| 4357 | if (btrfs_file_extent_type(leaf, fi) == |
| 4358 | BTRFS_FILE_EXTENT_INLINE) { |
| 4359 | ptr = btrfs_item_ptr_offset(leaf, slot); |
| 4360 | memmove_extent_buffer(leaf, ptr, |
| 4361 | (unsigned long)fi, |
| 4362 | offsetof(struct btrfs_file_extent_item, |
| 4363 | disk_bytenr)); |
| 4364 | } |
| 4365 | } |
| 4366 | |
| 4367 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
| 4368 | data_end + size_diff, btrfs_leaf_data(leaf) + |
| 4369 | data_end, old_data_start - data_end); |
| 4370 | |
| 4371 | offset = btrfs_disk_key_offset(&disk_key); |
| 4372 | btrfs_set_disk_key_offset(&disk_key, offset + size_diff); |
| 4373 | btrfs_set_item_key(leaf, &disk_key, slot); |
| 4374 | if (slot == 0) |
| 4375 | fixup_low_keys(trans, root, path, &disk_key, 1); |
| 4376 | } |
| 4377 | |
| 4378 | item = btrfs_item_nr(leaf, slot); |
| 4379 | btrfs_set_item_size(leaf, item, new_size); |
| 4380 | btrfs_mark_buffer_dirty(leaf); |
| 4381 | |
| 4382 | if (btrfs_leaf_free_space(root, leaf) < 0) { |
| 4383 | btrfs_print_leaf(root, leaf); |
| 4384 | BUG(); |
| 4385 | } |
| 4386 | } |
| 4387 | |
| 4388 | /* |
| 4389 | * make the item pointed to by the path bigger, data_size is the new size. |
| 4390 | */ |
| 4391 | void btrfs_extend_item(struct btrfs_trans_handle *trans, |
| 4392 | struct btrfs_root *root, struct btrfs_path *path, |
| 4393 | u32 data_size) |
| 4394 | { |
| 4395 | int slot; |
| 4396 | struct extent_buffer *leaf; |
| 4397 | struct btrfs_item *item; |
| 4398 | u32 nritems; |
| 4399 | unsigned int data_end; |
| 4400 | unsigned int old_data; |
| 4401 | unsigned int old_size; |
| 4402 | int i; |
| 4403 | struct btrfs_map_token token; |
| 4404 | |
| 4405 | btrfs_init_map_token(&token); |
| 4406 | |
| 4407 | leaf = path->nodes[0]; |
| 4408 | |
| 4409 | nritems = btrfs_header_nritems(leaf); |
| 4410 | data_end = leaf_data_end(root, leaf); |
| 4411 | |
| 4412 | if (btrfs_leaf_free_space(root, leaf) < data_size) { |
| 4413 | btrfs_print_leaf(root, leaf); |
| 4414 | BUG(); |
| 4415 | } |
| 4416 | slot = path->slots[0]; |
| 4417 | old_data = btrfs_item_end_nr(leaf, slot); |
| 4418 | |
| 4419 | BUG_ON(slot < 0); |
| 4420 | if (slot >= nritems) { |
| 4421 | btrfs_print_leaf(root, leaf); |
| 4422 | printk(KERN_CRIT "slot %d too large, nritems %d\n", |
| 4423 | slot, nritems); |
| 4424 | BUG_ON(1); |
| 4425 | } |
| 4426 | |
| 4427 | /* |
| 4428 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
| 4429 | */ |
| 4430 | /* first correct the data pointers */ |
| 4431 | for (i = slot; i < nritems; i++) { |
| 4432 | u32 ioff; |
| 4433 | item = btrfs_item_nr(leaf, i); |
| 4434 | |
| 4435 | ioff = btrfs_token_item_offset(leaf, item, &token); |
| 4436 | btrfs_set_token_item_offset(leaf, item, |
| 4437 | ioff - data_size, &token); |
| 4438 | } |
| 4439 | |
| 4440 | /* shift the data */ |
| 4441 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
| 4442 | data_end - data_size, btrfs_leaf_data(leaf) + |
| 4443 | data_end, old_data - data_end); |
| 4444 | |
| 4445 | data_end = old_data; |
| 4446 | old_size = btrfs_item_size_nr(leaf, slot); |
| 4447 | item = btrfs_item_nr(leaf, slot); |
| 4448 | btrfs_set_item_size(leaf, item, old_size + data_size); |
| 4449 | btrfs_mark_buffer_dirty(leaf); |
| 4450 | |
| 4451 | if (btrfs_leaf_free_space(root, leaf) < 0) { |
| 4452 | btrfs_print_leaf(root, leaf); |
| 4453 | BUG(); |
| 4454 | } |
| 4455 | } |
| 4456 | |
| 4457 | /* |
| 4458 | * this is a helper for btrfs_insert_empty_items, the main goal here is |
| 4459 | * to save stack depth by doing the bulk of the work in a function |
| 4460 | * that doesn't call btrfs_search_slot |
| 4461 | */ |
| 4462 | void setup_items_for_insert(struct btrfs_trans_handle *trans, |
| 4463 | struct btrfs_root *root, struct btrfs_path *path, |
| 4464 | struct btrfs_key *cpu_key, u32 *data_size, |
| 4465 | u32 total_data, u32 total_size, int nr) |
| 4466 | { |
| 4467 | struct btrfs_item *item; |
| 4468 | int i; |
| 4469 | u32 nritems; |
| 4470 | unsigned int data_end; |
| 4471 | struct btrfs_disk_key disk_key; |
| 4472 | struct extent_buffer *leaf; |
| 4473 | int slot; |
| 4474 | struct btrfs_map_token token; |
| 4475 | |
| 4476 | btrfs_init_map_token(&token); |
| 4477 | |
| 4478 | leaf = path->nodes[0]; |
| 4479 | slot = path->slots[0]; |
| 4480 | |
| 4481 | nritems = btrfs_header_nritems(leaf); |
| 4482 | data_end = leaf_data_end(root, leaf); |
| 4483 | |
| 4484 | if (btrfs_leaf_free_space(root, leaf) < total_size) { |
| 4485 | btrfs_print_leaf(root, leaf); |
| 4486 | printk(KERN_CRIT "not enough freespace need %u have %d\n", |
| 4487 | total_size, btrfs_leaf_free_space(root, leaf)); |
| 4488 | BUG(); |
| 4489 | } |
| 4490 | |
| 4491 | if (slot != nritems) { |
| 4492 | unsigned int old_data = btrfs_item_end_nr(leaf, slot); |
| 4493 | |
| 4494 | if (old_data < data_end) { |
| 4495 | btrfs_print_leaf(root, leaf); |
| 4496 | printk(KERN_CRIT "slot %d old_data %d data_end %d\n", |
| 4497 | slot, old_data, data_end); |
| 4498 | BUG_ON(1); |
| 4499 | } |
| 4500 | /* |
| 4501 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
| 4502 | */ |
| 4503 | /* first correct the data pointers */ |
| 4504 | for (i = slot; i < nritems; i++) { |
| 4505 | u32 ioff; |
| 4506 | |
| 4507 | item = btrfs_item_nr(leaf, i); |
| 4508 | ioff = btrfs_token_item_offset(leaf, item, &token); |
| 4509 | btrfs_set_token_item_offset(leaf, item, |
| 4510 | ioff - total_data, &token); |
| 4511 | } |
| 4512 | /* shift the items */ |
| 4513 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr), |
| 4514 | btrfs_item_nr_offset(slot), |
| 4515 | (nritems - slot) * sizeof(struct btrfs_item)); |
| 4516 | |
| 4517 | /* shift the data */ |
| 4518 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
| 4519 | data_end - total_data, btrfs_leaf_data(leaf) + |
| 4520 | data_end, old_data - data_end); |
| 4521 | data_end = old_data; |
| 4522 | } |
| 4523 | |
| 4524 | /* setup the item for the new data */ |
| 4525 | for (i = 0; i < nr; i++) { |
| 4526 | btrfs_cpu_key_to_disk(&disk_key, cpu_key + i); |
| 4527 | btrfs_set_item_key(leaf, &disk_key, slot + i); |
| 4528 | item = btrfs_item_nr(leaf, slot + i); |
| 4529 | btrfs_set_token_item_offset(leaf, item, |
| 4530 | data_end - data_size[i], &token); |
| 4531 | data_end -= data_size[i]; |
| 4532 | btrfs_set_token_item_size(leaf, item, data_size[i], &token); |
| 4533 | } |
| 4534 | |
| 4535 | btrfs_set_header_nritems(leaf, nritems + nr); |
| 4536 | |
| 4537 | if (slot == 0) { |
| 4538 | btrfs_cpu_key_to_disk(&disk_key, cpu_key); |
| 4539 | fixup_low_keys(trans, root, path, &disk_key, 1); |
| 4540 | } |
| 4541 | btrfs_unlock_up_safe(path, 1); |
| 4542 | btrfs_mark_buffer_dirty(leaf); |
| 4543 | |
| 4544 | if (btrfs_leaf_free_space(root, leaf) < 0) { |
| 4545 | btrfs_print_leaf(root, leaf); |
| 4546 | BUG(); |
| 4547 | } |
| 4548 | } |
| 4549 | |
| 4550 | /* |
| 4551 | * Given a key and some data, insert items into the tree. |
| 4552 | * This does all the path init required, making room in the tree if needed. |
| 4553 | */ |
| 4554 | int btrfs_insert_empty_items(struct btrfs_trans_handle *trans, |
| 4555 | struct btrfs_root *root, |
| 4556 | struct btrfs_path *path, |
| 4557 | struct btrfs_key *cpu_key, u32 *data_size, |
| 4558 | int nr) |
| 4559 | { |
| 4560 | int ret = 0; |
| 4561 | int slot; |
| 4562 | int i; |
| 4563 | u32 total_size = 0; |
| 4564 | u32 total_data = 0; |
| 4565 | |
| 4566 | for (i = 0; i < nr; i++) |
| 4567 | total_data += data_size[i]; |
| 4568 | |
| 4569 | total_size = total_data + (nr * sizeof(struct btrfs_item)); |
| 4570 | ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1); |
| 4571 | if (ret == 0) |
| 4572 | return -EEXIST; |
| 4573 | if (ret < 0) |
| 4574 | return ret; |
| 4575 | |
| 4576 | slot = path->slots[0]; |
| 4577 | BUG_ON(slot < 0); |
| 4578 | |
| 4579 | setup_items_for_insert(trans, root, path, cpu_key, data_size, |
| 4580 | total_data, total_size, nr); |
| 4581 | return 0; |
| 4582 | } |
| 4583 | |
| 4584 | /* |
| 4585 | * Given a key and some data, insert an item into the tree. |
| 4586 | * This does all the path init required, making room in the tree if needed. |
| 4587 | */ |
| 4588 | int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root |
| 4589 | *root, struct btrfs_key *cpu_key, void *data, u32 |
| 4590 | data_size) |
| 4591 | { |
| 4592 | int ret = 0; |
| 4593 | struct btrfs_path *path; |
| 4594 | struct extent_buffer *leaf; |
| 4595 | unsigned long ptr; |
| 4596 | |
| 4597 | path = btrfs_alloc_path(); |
| 4598 | if (!path) |
| 4599 | return -ENOMEM; |
| 4600 | ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); |
| 4601 | if (!ret) { |
| 4602 | leaf = path->nodes[0]; |
| 4603 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
| 4604 | write_extent_buffer(leaf, data, ptr, data_size); |
| 4605 | btrfs_mark_buffer_dirty(leaf); |
| 4606 | } |
| 4607 | btrfs_free_path(path); |
| 4608 | return ret; |
| 4609 | } |
| 4610 | |
| 4611 | /* |
| 4612 | * delete the pointer from a given node. |
| 4613 | * |
| 4614 | * the tree should have been previously balanced so the deletion does not |
| 4615 | * empty a node. |
| 4616 | */ |
| 4617 | static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 4618 | struct btrfs_path *path, int level, int slot) |
| 4619 | { |
| 4620 | struct extent_buffer *parent = path->nodes[level]; |
| 4621 | u32 nritems; |
| 4622 | int ret; |
| 4623 | |
| 4624 | nritems = btrfs_header_nritems(parent); |
| 4625 | if (slot != nritems - 1) { |
| 4626 | if (level) |
| 4627 | tree_mod_log_eb_move(root->fs_info, parent, slot, |
| 4628 | slot + 1, nritems - slot - 1); |
| 4629 | memmove_extent_buffer(parent, |
| 4630 | btrfs_node_key_ptr_offset(slot), |
| 4631 | btrfs_node_key_ptr_offset(slot + 1), |
| 4632 | sizeof(struct btrfs_key_ptr) * |
| 4633 | (nritems - slot - 1)); |
| 4634 | } else if (level) { |
| 4635 | ret = tree_mod_log_insert_key(root->fs_info, parent, slot, |
| 4636 | MOD_LOG_KEY_REMOVE); |
| 4637 | BUG_ON(ret < 0); |
| 4638 | } |
| 4639 | |
| 4640 | nritems--; |
| 4641 | btrfs_set_header_nritems(parent, nritems); |
| 4642 | if (nritems == 0 && parent == root->node) { |
| 4643 | BUG_ON(btrfs_header_level(root->node) != 1); |
| 4644 | /* just turn the root into a leaf and break */ |
| 4645 | btrfs_set_header_level(root->node, 0); |
| 4646 | } else if (slot == 0) { |
| 4647 | struct btrfs_disk_key disk_key; |
| 4648 | |
| 4649 | btrfs_node_key(parent, &disk_key, 0); |
| 4650 | fixup_low_keys(trans, root, path, &disk_key, level + 1); |
| 4651 | } |
| 4652 | btrfs_mark_buffer_dirty(parent); |
| 4653 | } |
| 4654 | |
| 4655 | /* |
| 4656 | * a helper function to delete the leaf pointed to by path->slots[1] and |
| 4657 | * path->nodes[1]. |
| 4658 | * |
| 4659 | * This deletes the pointer in path->nodes[1] and frees the leaf |
| 4660 | * block extent. zero is returned if it all worked out, < 0 otherwise. |
| 4661 | * |
| 4662 | * The path must have already been setup for deleting the leaf, including |
| 4663 | * all the proper balancing. path->nodes[1] must be locked. |
| 4664 | */ |
| 4665 | static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans, |
| 4666 | struct btrfs_root *root, |
| 4667 | struct btrfs_path *path, |
| 4668 | struct extent_buffer *leaf) |
| 4669 | { |
| 4670 | WARN_ON(btrfs_header_generation(leaf) != trans->transid); |
| 4671 | del_ptr(trans, root, path, 1, path->slots[1]); |
| 4672 | |
| 4673 | /* |
| 4674 | * btrfs_free_extent is expensive, we want to make sure we |
| 4675 | * aren't holding any locks when we call it |
| 4676 | */ |
| 4677 | btrfs_unlock_up_safe(path, 0); |
| 4678 | |
| 4679 | root_sub_used(root, leaf->len); |
| 4680 | |
| 4681 | extent_buffer_get(leaf); |
| 4682 | btrfs_free_tree_block(trans, root, leaf, 0, 1); |
| 4683 | free_extent_buffer_stale(leaf); |
| 4684 | } |
| 4685 | /* |
| 4686 | * delete the item at the leaf level in path. If that empties |
| 4687 | * the leaf, remove it from the tree |
| 4688 | */ |
| 4689 | int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 4690 | struct btrfs_path *path, int slot, int nr) |
| 4691 | { |
| 4692 | struct extent_buffer *leaf; |
| 4693 | struct btrfs_item *item; |
| 4694 | int last_off; |
| 4695 | int dsize = 0; |
| 4696 | int ret = 0; |
| 4697 | int wret; |
| 4698 | int i; |
| 4699 | u32 nritems; |
| 4700 | struct btrfs_map_token token; |
| 4701 | |
| 4702 | btrfs_init_map_token(&token); |
| 4703 | |
| 4704 | leaf = path->nodes[0]; |
| 4705 | last_off = btrfs_item_offset_nr(leaf, slot + nr - 1); |
| 4706 | |
| 4707 | for (i = 0; i < nr; i++) |
| 4708 | dsize += btrfs_item_size_nr(leaf, slot + i); |
| 4709 | |
| 4710 | nritems = btrfs_header_nritems(leaf); |
| 4711 | |
| 4712 | if (slot + nr != nritems) { |
| 4713 | int data_end = leaf_data_end(root, leaf); |
| 4714 | |
| 4715 | memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
| 4716 | data_end + dsize, |
| 4717 | btrfs_leaf_data(leaf) + data_end, |
| 4718 | last_off - data_end); |
| 4719 | |
| 4720 | for (i = slot + nr; i < nritems; i++) { |
| 4721 | u32 ioff; |
| 4722 | |
| 4723 | item = btrfs_item_nr(leaf, i); |
| 4724 | ioff = btrfs_token_item_offset(leaf, item, &token); |
| 4725 | btrfs_set_token_item_offset(leaf, item, |
| 4726 | ioff + dsize, &token); |
| 4727 | } |
| 4728 | |
| 4729 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot), |
| 4730 | btrfs_item_nr_offset(slot + nr), |
| 4731 | sizeof(struct btrfs_item) * |
| 4732 | (nritems - slot - nr)); |
| 4733 | } |
| 4734 | btrfs_set_header_nritems(leaf, nritems - nr); |
| 4735 | nritems -= nr; |
| 4736 | |
| 4737 | /* delete the leaf if we've emptied it */ |
| 4738 | if (nritems == 0) { |
| 4739 | if (leaf == root->node) { |
| 4740 | btrfs_set_header_level(leaf, 0); |
| 4741 | } else { |
| 4742 | btrfs_set_path_blocking(path); |
| 4743 | clean_tree_block(trans, root, leaf); |
| 4744 | btrfs_del_leaf(trans, root, path, leaf); |
| 4745 | } |
| 4746 | } else { |
| 4747 | int used = leaf_space_used(leaf, 0, nritems); |
| 4748 | if (slot == 0) { |
| 4749 | struct btrfs_disk_key disk_key; |
| 4750 | |
| 4751 | btrfs_item_key(leaf, &disk_key, 0); |
| 4752 | fixup_low_keys(trans, root, path, &disk_key, 1); |
| 4753 | } |
| 4754 | |
| 4755 | /* delete the leaf if it is mostly empty */ |
| 4756 | if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) { |
| 4757 | /* push_leaf_left fixes the path. |
| 4758 | * make sure the path still points to our leaf |
| 4759 | * for possible call to del_ptr below |
| 4760 | */ |
| 4761 | slot = path->slots[1]; |
| 4762 | extent_buffer_get(leaf); |
| 4763 | |
| 4764 | btrfs_set_path_blocking(path); |
| 4765 | wret = push_leaf_left(trans, root, path, 1, 1, |
| 4766 | 1, (u32)-1); |
| 4767 | if (wret < 0 && wret != -ENOSPC) |
| 4768 | ret = wret; |
| 4769 | |
| 4770 | if (path->nodes[0] == leaf && |
| 4771 | btrfs_header_nritems(leaf)) { |
| 4772 | wret = push_leaf_right(trans, root, path, 1, |
| 4773 | 1, 1, 0); |
| 4774 | if (wret < 0 && wret != -ENOSPC) |
| 4775 | ret = wret; |
| 4776 | } |
| 4777 | |
| 4778 | if (btrfs_header_nritems(leaf) == 0) { |
| 4779 | path->slots[1] = slot; |
| 4780 | btrfs_del_leaf(trans, root, path, leaf); |
| 4781 | free_extent_buffer(leaf); |
| 4782 | ret = 0; |
| 4783 | } else { |
| 4784 | /* if we're still in the path, make sure |
| 4785 | * we're dirty. Otherwise, one of the |
| 4786 | * push_leaf functions must have already |
| 4787 | * dirtied this buffer |
| 4788 | */ |
| 4789 | if (path->nodes[0] == leaf) |
| 4790 | btrfs_mark_buffer_dirty(leaf); |
| 4791 | free_extent_buffer(leaf); |
| 4792 | } |
| 4793 | } else { |
| 4794 | btrfs_mark_buffer_dirty(leaf); |
| 4795 | } |
| 4796 | } |
| 4797 | return ret; |
| 4798 | } |
| 4799 | |
| 4800 | /* |
| 4801 | * search the tree again to find a leaf with lesser keys |
| 4802 | * returns 0 if it found something or 1 if there are no lesser leaves. |
| 4803 | * returns < 0 on io errors. |
| 4804 | * |
| 4805 | * This may release the path, and so you may lose any locks held at the |
| 4806 | * time you call it. |
| 4807 | */ |
| 4808 | int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) |
| 4809 | { |
| 4810 | struct btrfs_key key; |
| 4811 | struct btrfs_disk_key found_key; |
| 4812 | int ret; |
| 4813 | |
| 4814 | btrfs_item_key_to_cpu(path->nodes[0], &key, 0); |
| 4815 | |
| 4816 | if (key.offset > 0) |
| 4817 | key.offset--; |
| 4818 | else if (key.type > 0) |
| 4819 | key.type--; |
| 4820 | else if (key.objectid > 0) |
| 4821 | key.objectid--; |
| 4822 | else |
| 4823 | return 1; |
| 4824 | |
| 4825 | btrfs_release_path(path); |
| 4826 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
| 4827 | if (ret < 0) |
| 4828 | return ret; |
| 4829 | btrfs_item_key(path->nodes[0], &found_key, 0); |
| 4830 | ret = comp_keys(&found_key, &key); |
| 4831 | if (ret < 0) |
| 4832 | return 0; |
| 4833 | return 1; |
| 4834 | } |
| 4835 | |
| 4836 | /* |
| 4837 | * A helper function to walk down the tree starting at min_key, and looking |
| 4838 | * for nodes or leaves that are have a minimum transaction id. |
| 4839 | * This is used by the btree defrag code, and tree logging |
| 4840 | * |
| 4841 | * This does not cow, but it does stuff the starting key it finds back |
| 4842 | * into min_key, so you can call btrfs_search_slot with cow=1 on the |
| 4843 | * key and get a writable path. |
| 4844 | * |
| 4845 | * This does lock as it descends, and path->keep_locks should be set |
| 4846 | * to 1 by the caller. |
| 4847 | * |
| 4848 | * This honors path->lowest_level to prevent descent past a given level |
| 4849 | * of the tree. |
| 4850 | * |
| 4851 | * min_trans indicates the oldest transaction that you are interested |
| 4852 | * in walking through. Any nodes or leaves older than min_trans are |
| 4853 | * skipped over (without reading them). |
| 4854 | * |
| 4855 | * returns zero if something useful was found, < 0 on error and 1 if there |
| 4856 | * was nothing in the tree that matched the search criteria. |
| 4857 | */ |
| 4858 | int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, |
| 4859 | struct btrfs_key *max_key, |
| 4860 | struct btrfs_path *path, |
| 4861 | u64 min_trans) |
| 4862 | { |
| 4863 | struct extent_buffer *cur; |
| 4864 | struct btrfs_key found_key; |
| 4865 | int slot; |
| 4866 | int sret; |
| 4867 | u32 nritems; |
| 4868 | int level; |
| 4869 | int ret = 1; |
| 4870 | |
| 4871 | WARN_ON(!path->keep_locks); |
| 4872 | again: |
| 4873 | cur = btrfs_read_lock_root_node(root); |
| 4874 | level = btrfs_header_level(cur); |
| 4875 | WARN_ON(path->nodes[level]); |
| 4876 | path->nodes[level] = cur; |
| 4877 | path->locks[level] = BTRFS_READ_LOCK; |
| 4878 | |
| 4879 | if (btrfs_header_generation(cur) < min_trans) { |
| 4880 | ret = 1; |
| 4881 | goto out; |
| 4882 | } |
| 4883 | while (1) { |
| 4884 | nritems = btrfs_header_nritems(cur); |
| 4885 | level = btrfs_header_level(cur); |
| 4886 | sret = bin_search(cur, min_key, level, &slot); |
| 4887 | |
| 4888 | /* at the lowest level, we're done, setup the path and exit */ |
| 4889 | if (level == path->lowest_level) { |
| 4890 | if (slot >= nritems) |
| 4891 | goto find_next_key; |
| 4892 | ret = 0; |
| 4893 | path->slots[level] = slot; |
| 4894 | btrfs_item_key_to_cpu(cur, &found_key, slot); |
| 4895 | goto out; |
| 4896 | } |
| 4897 | if (sret && slot > 0) |
| 4898 | slot--; |
| 4899 | /* |
| 4900 | * check this node pointer against the min_trans parameters. |
| 4901 | * If it is too old, old, skip to the next one. |
| 4902 | */ |
| 4903 | while (slot < nritems) { |
| 4904 | u64 blockptr; |
| 4905 | u64 gen; |
| 4906 | |
| 4907 | blockptr = btrfs_node_blockptr(cur, slot); |
| 4908 | gen = btrfs_node_ptr_generation(cur, slot); |
| 4909 | if (gen < min_trans) { |
| 4910 | slot++; |
| 4911 | continue; |
| 4912 | } |
| 4913 | break; |
| 4914 | } |
| 4915 | find_next_key: |
| 4916 | /* |
| 4917 | * we didn't find a candidate key in this node, walk forward |
| 4918 | * and find another one |
| 4919 | */ |
| 4920 | if (slot >= nritems) { |
| 4921 | path->slots[level] = slot; |
| 4922 | btrfs_set_path_blocking(path); |
| 4923 | sret = btrfs_find_next_key(root, path, min_key, level, |
| 4924 | min_trans); |
| 4925 | if (sret == 0) { |
| 4926 | btrfs_release_path(path); |
| 4927 | goto again; |
| 4928 | } else { |
| 4929 | goto out; |
| 4930 | } |
| 4931 | } |
| 4932 | /* save our key for returning back */ |
| 4933 | btrfs_node_key_to_cpu(cur, &found_key, slot); |
| 4934 | path->slots[level] = slot; |
| 4935 | if (level == path->lowest_level) { |
| 4936 | ret = 0; |
| 4937 | unlock_up(path, level, 1, 0, NULL); |
| 4938 | goto out; |
| 4939 | } |
| 4940 | btrfs_set_path_blocking(path); |
| 4941 | cur = read_node_slot(root, cur, slot); |
| 4942 | BUG_ON(!cur); /* -ENOMEM */ |
| 4943 | |
| 4944 | btrfs_tree_read_lock(cur); |
| 4945 | |
| 4946 | path->locks[level - 1] = BTRFS_READ_LOCK; |
| 4947 | path->nodes[level - 1] = cur; |
| 4948 | unlock_up(path, level, 1, 0, NULL); |
| 4949 | btrfs_clear_path_blocking(path, NULL, 0); |
| 4950 | } |
| 4951 | out: |
| 4952 | if (ret == 0) |
| 4953 | memcpy(min_key, &found_key, sizeof(found_key)); |
| 4954 | btrfs_set_path_blocking(path); |
| 4955 | return ret; |
| 4956 | } |
| 4957 | |
| 4958 | static void tree_move_down(struct btrfs_root *root, |
| 4959 | struct btrfs_path *path, |
| 4960 | int *level, int root_level) |
| 4961 | { |
| 4962 | BUG_ON(*level == 0); |
| 4963 | path->nodes[*level - 1] = read_node_slot(root, path->nodes[*level], |
| 4964 | path->slots[*level]); |
| 4965 | path->slots[*level - 1] = 0; |
| 4966 | (*level)--; |
| 4967 | } |
| 4968 | |
| 4969 | static int tree_move_next_or_upnext(struct btrfs_root *root, |
| 4970 | struct btrfs_path *path, |
| 4971 | int *level, int root_level) |
| 4972 | { |
| 4973 | int ret = 0; |
| 4974 | int nritems; |
| 4975 | nritems = btrfs_header_nritems(path->nodes[*level]); |
| 4976 | |
| 4977 | path->slots[*level]++; |
| 4978 | |
| 4979 | while (path->slots[*level] >= nritems) { |
| 4980 | if (*level == root_level) |
| 4981 | return -1; |
| 4982 | |
| 4983 | /* move upnext */ |
| 4984 | path->slots[*level] = 0; |
| 4985 | free_extent_buffer(path->nodes[*level]); |
| 4986 | path->nodes[*level] = NULL; |
| 4987 | (*level)++; |
| 4988 | path->slots[*level]++; |
| 4989 | |
| 4990 | nritems = btrfs_header_nritems(path->nodes[*level]); |
| 4991 | ret = 1; |
| 4992 | } |
| 4993 | return ret; |
| 4994 | } |
| 4995 | |
| 4996 | /* |
| 4997 | * Returns 1 if it had to move up and next. 0 is returned if it moved only next |
| 4998 | * or down. |
| 4999 | */ |
| 5000 | static int tree_advance(struct btrfs_root *root, |
| 5001 | struct btrfs_path *path, |
| 5002 | int *level, int root_level, |
| 5003 | int allow_down, |
| 5004 | struct btrfs_key *key) |
| 5005 | { |
| 5006 | int ret; |
| 5007 | |
| 5008 | if (*level == 0 || !allow_down) { |
| 5009 | ret = tree_move_next_or_upnext(root, path, level, root_level); |
| 5010 | } else { |
| 5011 | tree_move_down(root, path, level, root_level); |
| 5012 | ret = 0; |
| 5013 | } |
| 5014 | if (ret >= 0) { |
| 5015 | if (*level == 0) |
| 5016 | btrfs_item_key_to_cpu(path->nodes[*level], key, |
| 5017 | path->slots[*level]); |
| 5018 | else |
| 5019 | btrfs_node_key_to_cpu(path->nodes[*level], key, |
| 5020 | path->slots[*level]); |
| 5021 | } |
| 5022 | return ret; |
| 5023 | } |
| 5024 | |
| 5025 | static int tree_compare_item(struct btrfs_root *left_root, |
| 5026 | struct btrfs_path *left_path, |
| 5027 | struct btrfs_path *right_path, |
| 5028 | char *tmp_buf) |
| 5029 | { |
| 5030 | int cmp; |
| 5031 | int len1, len2; |
| 5032 | unsigned long off1, off2; |
| 5033 | |
| 5034 | len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]); |
| 5035 | len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]); |
| 5036 | if (len1 != len2) |
| 5037 | return 1; |
| 5038 | |
| 5039 | off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]); |
| 5040 | off2 = btrfs_item_ptr_offset(right_path->nodes[0], |
| 5041 | right_path->slots[0]); |
| 5042 | |
| 5043 | read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1); |
| 5044 | |
| 5045 | cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1); |
| 5046 | if (cmp) |
| 5047 | return 1; |
| 5048 | return 0; |
| 5049 | } |
| 5050 | |
| 5051 | #define ADVANCE 1 |
| 5052 | #define ADVANCE_ONLY_NEXT -1 |
| 5053 | |
| 5054 | /* |
| 5055 | * This function compares two trees and calls the provided callback for |
| 5056 | * every changed/new/deleted item it finds. |
| 5057 | * If shared tree blocks are encountered, whole subtrees are skipped, making |
| 5058 | * the compare pretty fast on snapshotted subvolumes. |
| 5059 | * |
| 5060 | * This currently works on commit roots only. As commit roots are read only, |
| 5061 | * we don't do any locking. The commit roots are protected with transactions. |
| 5062 | * Transactions are ended and rejoined when a commit is tried in between. |
| 5063 | * |
| 5064 | * This function checks for modifications done to the trees while comparing. |
| 5065 | * If it detects a change, it aborts immediately. |
| 5066 | */ |
| 5067 | int btrfs_compare_trees(struct btrfs_root *left_root, |
| 5068 | struct btrfs_root *right_root, |
| 5069 | btrfs_changed_cb_t changed_cb, void *ctx) |
| 5070 | { |
| 5071 | int ret; |
| 5072 | int cmp; |
| 5073 | struct btrfs_trans_handle *trans = NULL; |
| 5074 | struct btrfs_path *left_path = NULL; |
| 5075 | struct btrfs_path *right_path = NULL; |
| 5076 | struct btrfs_key left_key; |
| 5077 | struct btrfs_key right_key; |
| 5078 | char *tmp_buf = NULL; |
| 5079 | int left_root_level; |
| 5080 | int right_root_level; |
| 5081 | int left_level; |
| 5082 | int right_level; |
| 5083 | int left_end_reached; |
| 5084 | int right_end_reached; |
| 5085 | int advance_left; |
| 5086 | int advance_right; |
| 5087 | u64 left_blockptr; |
| 5088 | u64 right_blockptr; |
| 5089 | u64 left_start_ctransid; |
| 5090 | u64 right_start_ctransid; |
| 5091 | u64 ctransid; |
| 5092 | |
| 5093 | left_path = btrfs_alloc_path(); |
| 5094 | if (!left_path) { |
| 5095 | ret = -ENOMEM; |
| 5096 | goto out; |
| 5097 | } |
| 5098 | right_path = btrfs_alloc_path(); |
| 5099 | if (!right_path) { |
| 5100 | ret = -ENOMEM; |
| 5101 | goto out; |
| 5102 | } |
| 5103 | |
| 5104 | tmp_buf = kmalloc(left_root->leafsize, GFP_NOFS); |
| 5105 | if (!tmp_buf) { |
| 5106 | ret = -ENOMEM; |
| 5107 | goto out; |
| 5108 | } |
| 5109 | |
| 5110 | left_path->search_commit_root = 1; |
| 5111 | left_path->skip_locking = 1; |
| 5112 | right_path->search_commit_root = 1; |
| 5113 | right_path->skip_locking = 1; |
| 5114 | |
| 5115 | spin_lock(&left_root->root_item_lock); |
| 5116 | left_start_ctransid = btrfs_root_ctransid(&left_root->root_item); |
| 5117 | spin_unlock(&left_root->root_item_lock); |
| 5118 | |
| 5119 | spin_lock(&right_root->root_item_lock); |
| 5120 | right_start_ctransid = btrfs_root_ctransid(&right_root->root_item); |
| 5121 | spin_unlock(&right_root->root_item_lock); |
| 5122 | |
| 5123 | trans = btrfs_join_transaction(left_root); |
| 5124 | if (IS_ERR(trans)) { |
| 5125 | ret = PTR_ERR(trans); |
| 5126 | trans = NULL; |
| 5127 | goto out; |
| 5128 | } |
| 5129 | |
| 5130 | /* |
| 5131 | * Strategy: Go to the first items of both trees. Then do |
| 5132 | * |
| 5133 | * If both trees are at level 0 |
| 5134 | * Compare keys of current items |
| 5135 | * If left < right treat left item as new, advance left tree |
| 5136 | * and repeat |
| 5137 | * If left > right treat right item as deleted, advance right tree |
| 5138 | * and repeat |
| 5139 | * If left == right do deep compare of items, treat as changed if |
| 5140 | * needed, advance both trees and repeat |
| 5141 | * If both trees are at the same level but not at level 0 |
| 5142 | * Compare keys of current nodes/leafs |
| 5143 | * If left < right advance left tree and repeat |
| 5144 | * If left > right advance right tree and repeat |
| 5145 | * If left == right compare blockptrs of the next nodes/leafs |
| 5146 | * If they match advance both trees but stay at the same level |
| 5147 | * and repeat |
| 5148 | * If they don't match advance both trees while allowing to go |
| 5149 | * deeper and repeat |
| 5150 | * If tree levels are different |
| 5151 | * Advance the tree that needs it and repeat |
| 5152 | * |
| 5153 | * Advancing a tree means: |
| 5154 | * If we are at level 0, try to go to the next slot. If that's not |
| 5155 | * possible, go one level up and repeat. Stop when we found a level |
| 5156 | * where we could go to the next slot. We may at this point be on a |
| 5157 | * node or a leaf. |
| 5158 | * |
| 5159 | * If we are not at level 0 and not on shared tree blocks, go one |
| 5160 | * level deeper. |
| 5161 | * |
| 5162 | * If we are not at level 0 and on shared tree blocks, go one slot to |
| 5163 | * the right if possible or go up and right. |
| 5164 | */ |
| 5165 | |
| 5166 | left_level = btrfs_header_level(left_root->commit_root); |
| 5167 | left_root_level = left_level; |
| 5168 | left_path->nodes[left_level] = left_root->commit_root; |
| 5169 | extent_buffer_get(left_path->nodes[left_level]); |
| 5170 | |
| 5171 | right_level = btrfs_header_level(right_root->commit_root); |
| 5172 | right_root_level = right_level; |
| 5173 | right_path->nodes[right_level] = right_root->commit_root; |
| 5174 | extent_buffer_get(right_path->nodes[right_level]); |
| 5175 | |
| 5176 | if (left_level == 0) |
| 5177 | btrfs_item_key_to_cpu(left_path->nodes[left_level], |
| 5178 | &left_key, left_path->slots[left_level]); |
| 5179 | else |
| 5180 | btrfs_node_key_to_cpu(left_path->nodes[left_level], |
| 5181 | &left_key, left_path->slots[left_level]); |
| 5182 | if (right_level == 0) |
| 5183 | btrfs_item_key_to_cpu(right_path->nodes[right_level], |
| 5184 | &right_key, right_path->slots[right_level]); |
| 5185 | else |
| 5186 | btrfs_node_key_to_cpu(right_path->nodes[right_level], |
| 5187 | &right_key, right_path->slots[right_level]); |
| 5188 | |
| 5189 | left_end_reached = right_end_reached = 0; |
| 5190 | advance_left = advance_right = 0; |
| 5191 | |
| 5192 | while (1) { |
| 5193 | /* |
| 5194 | * We need to make sure the transaction does not get committed |
| 5195 | * while we do anything on commit roots. This means, we need to |
| 5196 | * join and leave transactions for every item that we process. |
| 5197 | */ |
| 5198 | if (trans && btrfs_should_end_transaction(trans, left_root)) { |
| 5199 | btrfs_release_path(left_path); |
| 5200 | btrfs_release_path(right_path); |
| 5201 | |
| 5202 | ret = btrfs_end_transaction(trans, left_root); |
| 5203 | trans = NULL; |
| 5204 | if (ret < 0) |
| 5205 | goto out; |
| 5206 | } |
| 5207 | /* now rejoin the transaction */ |
| 5208 | if (!trans) { |
| 5209 | trans = btrfs_join_transaction(left_root); |
| 5210 | if (IS_ERR(trans)) { |
| 5211 | ret = PTR_ERR(trans); |
| 5212 | trans = NULL; |
| 5213 | goto out; |
| 5214 | } |
| 5215 | |
| 5216 | spin_lock(&left_root->root_item_lock); |
| 5217 | ctransid = btrfs_root_ctransid(&left_root->root_item); |
| 5218 | spin_unlock(&left_root->root_item_lock); |
| 5219 | if (ctransid != left_start_ctransid) |
| 5220 | left_start_ctransid = 0; |
| 5221 | |
| 5222 | spin_lock(&right_root->root_item_lock); |
| 5223 | ctransid = btrfs_root_ctransid(&right_root->root_item); |
| 5224 | spin_unlock(&right_root->root_item_lock); |
| 5225 | if (ctransid != right_start_ctransid) |
| 5226 | right_start_ctransid = 0; |
| 5227 | |
| 5228 | if (!left_start_ctransid || !right_start_ctransid) { |
| 5229 | WARN(1, KERN_WARNING |
| 5230 | "btrfs: btrfs_compare_tree detected " |
| 5231 | "a change in one of the trees while " |
| 5232 | "iterating. This is probably a " |
| 5233 | "bug.\n"); |
| 5234 | ret = -EIO; |
| 5235 | goto out; |
| 5236 | } |
| 5237 | |
| 5238 | /* |
| 5239 | * the commit root may have changed, so start again |
| 5240 | * where we stopped |
| 5241 | */ |
| 5242 | left_path->lowest_level = left_level; |
| 5243 | right_path->lowest_level = right_level; |
| 5244 | ret = btrfs_search_slot(NULL, left_root, |
| 5245 | &left_key, left_path, 0, 0); |
| 5246 | if (ret < 0) |
| 5247 | goto out; |
| 5248 | ret = btrfs_search_slot(NULL, right_root, |
| 5249 | &right_key, right_path, 0, 0); |
| 5250 | if (ret < 0) |
| 5251 | goto out; |
| 5252 | } |
| 5253 | |
| 5254 | if (advance_left && !left_end_reached) { |
| 5255 | ret = tree_advance(left_root, left_path, &left_level, |
| 5256 | left_root_level, |
| 5257 | advance_left != ADVANCE_ONLY_NEXT, |
| 5258 | &left_key); |
| 5259 | if (ret < 0) |
| 5260 | left_end_reached = ADVANCE; |
| 5261 | advance_left = 0; |
| 5262 | } |
| 5263 | if (advance_right && !right_end_reached) { |
| 5264 | ret = tree_advance(right_root, right_path, &right_level, |
| 5265 | right_root_level, |
| 5266 | advance_right != ADVANCE_ONLY_NEXT, |
| 5267 | &right_key); |
| 5268 | if (ret < 0) |
| 5269 | right_end_reached = ADVANCE; |
| 5270 | advance_right = 0; |
| 5271 | } |
| 5272 | |
| 5273 | if (left_end_reached && right_end_reached) { |
| 5274 | ret = 0; |
| 5275 | goto out; |
| 5276 | } else if (left_end_reached) { |
| 5277 | if (right_level == 0) { |
| 5278 | ret = changed_cb(left_root, right_root, |
| 5279 | left_path, right_path, |
| 5280 | &right_key, |
| 5281 | BTRFS_COMPARE_TREE_DELETED, |
| 5282 | ctx); |
| 5283 | if (ret < 0) |
| 5284 | goto out; |
| 5285 | } |
| 5286 | advance_right = ADVANCE; |
| 5287 | continue; |
| 5288 | } else if (right_end_reached) { |
| 5289 | if (left_level == 0) { |
| 5290 | ret = changed_cb(left_root, right_root, |
| 5291 | left_path, right_path, |
| 5292 | &left_key, |
| 5293 | BTRFS_COMPARE_TREE_NEW, |
| 5294 | ctx); |
| 5295 | if (ret < 0) |
| 5296 | goto out; |
| 5297 | } |
| 5298 | advance_left = ADVANCE; |
| 5299 | continue; |
| 5300 | } |
| 5301 | |
| 5302 | if (left_level == 0 && right_level == 0) { |
| 5303 | cmp = btrfs_comp_cpu_keys(&left_key, &right_key); |
| 5304 | if (cmp < 0) { |
| 5305 | ret = changed_cb(left_root, right_root, |
| 5306 | left_path, right_path, |
| 5307 | &left_key, |
| 5308 | BTRFS_COMPARE_TREE_NEW, |
| 5309 | ctx); |
| 5310 | if (ret < 0) |
| 5311 | goto out; |
| 5312 | advance_left = ADVANCE; |
| 5313 | } else if (cmp > 0) { |
| 5314 | ret = changed_cb(left_root, right_root, |
| 5315 | left_path, right_path, |
| 5316 | &right_key, |
| 5317 | BTRFS_COMPARE_TREE_DELETED, |
| 5318 | ctx); |
| 5319 | if (ret < 0) |
| 5320 | goto out; |
| 5321 | advance_right = ADVANCE; |
| 5322 | } else { |
| 5323 | WARN_ON(!extent_buffer_uptodate(left_path->nodes[0])); |
| 5324 | ret = tree_compare_item(left_root, left_path, |
| 5325 | right_path, tmp_buf); |
| 5326 | if (ret) { |
| 5327 | WARN_ON(!extent_buffer_uptodate(left_path->nodes[0])); |
| 5328 | ret = changed_cb(left_root, right_root, |
| 5329 | left_path, right_path, |
| 5330 | &left_key, |
| 5331 | BTRFS_COMPARE_TREE_CHANGED, |
| 5332 | ctx); |
| 5333 | if (ret < 0) |
| 5334 | goto out; |
| 5335 | } |
| 5336 | advance_left = ADVANCE; |
| 5337 | advance_right = ADVANCE; |
| 5338 | } |
| 5339 | } else if (left_level == right_level) { |
| 5340 | cmp = btrfs_comp_cpu_keys(&left_key, &right_key); |
| 5341 | if (cmp < 0) { |
| 5342 | advance_left = ADVANCE; |
| 5343 | } else if (cmp > 0) { |
| 5344 | advance_right = ADVANCE; |
| 5345 | } else { |
| 5346 | left_blockptr = btrfs_node_blockptr( |
| 5347 | left_path->nodes[left_level], |
| 5348 | left_path->slots[left_level]); |
| 5349 | right_blockptr = btrfs_node_blockptr( |
| 5350 | right_path->nodes[right_level], |
| 5351 | right_path->slots[right_level]); |
| 5352 | if (left_blockptr == right_blockptr) { |
| 5353 | /* |
| 5354 | * As we're on a shared block, don't |
| 5355 | * allow to go deeper. |
| 5356 | */ |
| 5357 | advance_left = ADVANCE_ONLY_NEXT; |
| 5358 | advance_right = ADVANCE_ONLY_NEXT; |
| 5359 | } else { |
| 5360 | advance_left = ADVANCE; |
| 5361 | advance_right = ADVANCE; |
| 5362 | } |
| 5363 | } |
| 5364 | } else if (left_level < right_level) { |
| 5365 | advance_right = ADVANCE; |
| 5366 | } else { |
| 5367 | advance_left = ADVANCE; |
| 5368 | } |
| 5369 | } |
| 5370 | |
| 5371 | out: |
| 5372 | btrfs_free_path(left_path); |
| 5373 | btrfs_free_path(right_path); |
| 5374 | kfree(tmp_buf); |
| 5375 | |
| 5376 | if (trans) { |
| 5377 | if (!ret) |
| 5378 | ret = btrfs_end_transaction(trans, left_root); |
| 5379 | else |
| 5380 | btrfs_end_transaction(trans, left_root); |
| 5381 | } |
| 5382 | |
| 5383 | return ret; |
| 5384 | } |
| 5385 | |
| 5386 | /* |
| 5387 | * this is similar to btrfs_next_leaf, but does not try to preserve |
| 5388 | * and fixup the path. It looks for and returns the next key in the |
| 5389 | * tree based on the current path and the min_trans parameters. |
| 5390 | * |
| 5391 | * 0 is returned if another key is found, < 0 if there are any errors |
| 5392 | * and 1 is returned if there are no higher keys in the tree |
| 5393 | * |
| 5394 | * path->keep_locks should be set to 1 on the search made before |
| 5395 | * calling this function. |
| 5396 | */ |
| 5397 | int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path, |
| 5398 | struct btrfs_key *key, int level, u64 min_trans) |
| 5399 | { |
| 5400 | int slot; |
| 5401 | struct extent_buffer *c; |
| 5402 | |
| 5403 | WARN_ON(!path->keep_locks); |
| 5404 | while (level < BTRFS_MAX_LEVEL) { |
| 5405 | if (!path->nodes[level]) |
| 5406 | return 1; |
| 5407 | |
| 5408 | slot = path->slots[level] + 1; |
| 5409 | c = path->nodes[level]; |
| 5410 | next: |
| 5411 | if (slot >= btrfs_header_nritems(c)) { |
| 5412 | int ret; |
| 5413 | int orig_lowest; |
| 5414 | struct btrfs_key cur_key; |
| 5415 | if (level + 1 >= BTRFS_MAX_LEVEL || |
| 5416 | !path->nodes[level + 1]) |
| 5417 | return 1; |
| 5418 | |
| 5419 | if (path->locks[level + 1]) { |
| 5420 | level++; |
| 5421 | continue; |
| 5422 | } |
| 5423 | |
| 5424 | slot = btrfs_header_nritems(c) - 1; |
| 5425 | if (level == 0) |
| 5426 | btrfs_item_key_to_cpu(c, &cur_key, slot); |
| 5427 | else |
| 5428 | btrfs_node_key_to_cpu(c, &cur_key, slot); |
| 5429 | |
| 5430 | orig_lowest = path->lowest_level; |
| 5431 | btrfs_release_path(path); |
| 5432 | path->lowest_level = level; |
| 5433 | ret = btrfs_search_slot(NULL, root, &cur_key, path, |
| 5434 | 0, 0); |
| 5435 | path->lowest_level = orig_lowest; |
| 5436 | if (ret < 0) |
| 5437 | return ret; |
| 5438 | |
| 5439 | c = path->nodes[level]; |
| 5440 | slot = path->slots[level]; |
| 5441 | if (ret == 0) |
| 5442 | slot++; |
| 5443 | goto next; |
| 5444 | } |
| 5445 | |
| 5446 | if (level == 0) |
| 5447 | btrfs_item_key_to_cpu(c, key, slot); |
| 5448 | else { |
| 5449 | u64 gen = btrfs_node_ptr_generation(c, slot); |
| 5450 | |
| 5451 | if (gen < min_trans) { |
| 5452 | slot++; |
| 5453 | goto next; |
| 5454 | } |
| 5455 | btrfs_node_key_to_cpu(c, key, slot); |
| 5456 | } |
| 5457 | return 0; |
| 5458 | } |
| 5459 | return 1; |
| 5460 | } |
| 5461 | |
| 5462 | /* |
| 5463 | * search the tree again to find a leaf with greater keys |
| 5464 | * returns 0 if it found something or 1 if there are no greater leaves. |
| 5465 | * returns < 0 on io errors. |
| 5466 | */ |
| 5467 | int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) |
| 5468 | { |
| 5469 | return btrfs_next_old_leaf(root, path, 0); |
| 5470 | } |
| 5471 | |
| 5472 | int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, |
| 5473 | u64 time_seq) |
| 5474 | { |
| 5475 | int slot; |
| 5476 | int level; |
| 5477 | struct extent_buffer *c; |
| 5478 | struct extent_buffer *next; |
| 5479 | struct btrfs_key key; |
| 5480 | u32 nritems; |
| 5481 | int ret; |
| 5482 | int old_spinning = path->leave_spinning; |
| 5483 | int next_rw_lock = 0; |
| 5484 | |
| 5485 | nritems = btrfs_header_nritems(path->nodes[0]); |
| 5486 | if (nritems == 0) |
| 5487 | return 1; |
| 5488 | |
| 5489 | btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1); |
| 5490 | again: |
| 5491 | level = 1; |
| 5492 | next = NULL; |
| 5493 | next_rw_lock = 0; |
| 5494 | btrfs_release_path(path); |
| 5495 | |
| 5496 | path->keep_locks = 1; |
| 5497 | path->leave_spinning = 1; |
| 5498 | |
| 5499 | if (time_seq) |
| 5500 | ret = btrfs_search_old_slot(root, &key, path, time_seq); |
| 5501 | else |
| 5502 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
| 5503 | path->keep_locks = 0; |
| 5504 | |
| 5505 | if (ret < 0) |
| 5506 | return ret; |
| 5507 | |
| 5508 | nritems = btrfs_header_nritems(path->nodes[0]); |
| 5509 | /* |
| 5510 | * by releasing the path above we dropped all our locks. A balance |
| 5511 | * could have added more items next to the key that used to be |
| 5512 | * at the very end of the block. So, check again here and |
| 5513 | * advance the path if there are now more items available. |
| 5514 | */ |
| 5515 | if (nritems > 0 && path->slots[0] < nritems - 1) { |
| 5516 | if (ret == 0) |
| 5517 | path->slots[0]++; |
| 5518 | ret = 0; |
| 5519 | goto done; |
| 5520 | } |
| 5521 | |
| 5522 | while (level < BTRFS_MAX_LEVEL) { |
| 5523 | if (!path->nodes[level]) { |
| 5524 | ret = 1; |
| 5525 | goto done; |
| 5526 | } |
| 5527 | |
| 5528 | slot = path->slots[level] + 1; |
| 5529 | c = path->nodes[level]; |
| 5530 | if (slot >= btrfs_header_nritems(c)) { |
| 5531 | level++; |
| 5532 | if (level == BTRFS_MAX_LEVEL) { |
| 5533 | ret = 1; |
| 5534 | goto done; |
| 5535 | } |
| 5536 | continue; |
| 5537 | } |
| 5538 | |
| 5539 | if (next) { |
| 5540 | btrfs_tree_unlock_rw(next, next_rw_lock); |
| 5541 | free_extent_buffer(next); |
| 5542 | } |
| 5543 | |
| 5544 | next = c; |
| 5545 | next_rw_lock = path->locks[level]; |
| 5546 | ret = read_block_for_search(NULL, root, path, &next, level, |
| 5547 | slot, &key, 0); |
| 5548 | if (ret == -EAGAIN) |
| 5549 | goto again; |
| 5550 | |
| 5551 | if (ret < 0) { |
| 5552 | btrfs_release_path(path); |
| 5553 | goto done; |
| 5554 | } |
| 5555 | |
| 5556 | if (!path->skip_locking) { |
| 5557 | ret = btrfs_try_tree_read_lock(next); |
| 5558 | if (!ret && time_seq) { |
| 5559 | /* |
| 5560 | * If we don't get the lock, we may be racing |
| 5561 | * with push_leaf_left, holding that lock while |
| 5562 | * itself waiting for the leaf we've currently |
| 5563 | * locked. To solve this situation, we give up |
| 5564 | * on our lock and cycle. |
| 5565 | */ |
| 5566 | free_extent_buffer(next); |
| 5567 | btrfs_release_path(path); |
| 5568 | cond_resched(); |
| 5569 | goto again; |
| 5570 | } |
| 5571 | if (!ret) { |
| 5572 | btrfs_set_path_blocking(path); |
| 5573 | btrfs_tree_read_lock(next); |
| 5574 | btrfs_clear_path_blocking(path, next, |
| 5575 | BTRFS_READ_LOCK); |
| 5576 | } |
| 5577 | next_rw_lock = BTRFS_READ_LOCK; |
| 5578 | } |
| 5579 | break; |
| 5580 | } |
| 5581 | path->slots[level] = slot; |
| 5582 | while (1) { |
| 5583 | level--; |
| 5584 | c = path->nodes[level]; |
| 5585 | if (path->locks[level]) |
| 5586 | btrfs_tree_unlock_rw(c, path->locks[level]); |
| 5587 | |
| 5588 | free_extent_buffer(c); |
| 5589 | path->nodes[level] = next; |
| 5590 | path->slots[level] = 0; |
| 5591 | if (!path->skip_locking) |
| 5592 | path->locks[level] = next_rw_lock; |
| 5593 | if (!level) |
| 5594 | break; |
| 5595 | |
| 5596 | ret = read_block_for_search(NULL, root, path, &next, level, |
| 5597 | 0, &key, 0); |
| 5598 | if (ret == -EAGAIN) |
| 5599 | goto again; |
| 5600 | |
| 5601 | if (ret < 0) { |
| 5602 | btrfs_release_path(path); |
| 5603 | goto done; |
| 5604 | } |
| 5605 | |
| 5606 | if (!path->skip_locking) { |
| 5607 | ret = btrfs_try_tree_read_lock(next); |
| 5608 | if (!ret) { |
| 5609 | btrfs_set_path_blocking(path); |
| 5610 | btrfs_tree_read_lock(next); |
| 5611 | btrfs_clear_path_blocking(path, next, |
| 5612 | BTRFS_READ_LOCK); |
| 5613 | } |
| 5614 | next_rw_lock = BTRFS_READ_LOCK; |
| 5615 | } |
| 5616 | } |
| 5617 | ret = 0; |
| 5618 | done: |
| 5619 | unlock_up(path, 0, 1, 0, NULL); |
| 5620 | path->leave_spinning = old_spinning; |
| 5621 | if (!old_spinning) |
| 5622 | btrfs_set_path_blocking(path); |
| 5623 | |
| 5624 | return ret; |
| 5625 | } |
| 5626 | |
| 5627 | /* |
| 5628 | * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps |
| 5629 | * searching until it gets past min_objectid or finds an item of 'type' |
| 5630 | * |
| 5631 | * returns 0 if something is found, 1 if nothing was found and < 0 on error |
| 5632 | */ |
| 5633 | int btrfs_previous_item(struct btrfs_root *root, |
| 5634 | struct btrfs_path *path, u64 min_objectid, |
| 5635 | int type) |
| 5636 | { |
| 5637 | struct btrfs_key found_key; |
| 5638 | struct extent_buffer *leaf; |
| 5639 | u32 nritems; |
| 5640 | int ret; |
| 5641 | |
| 5642 | while (1) { |
| 5643 | if (path->slots[0] == 0) { |
| 5644 | btrfs_set_path_blocking(path); |
| 5645 | ret = btrfs_prev_leaf(root, path); |
| 5646 | if (ret != 0) |
| 5647 | return ret; |
| 5648 | } else { |
| 5649 | path->slots[0]--; |
| 5650 | } |
| 5651 | leaf = path->nodes[0]; |
| 5652 | nritems = btrfs_header_nritems(leaf); |
| 5653 | if (nritems == 0) |
| 5654 | return 1; |
| 5655 | if (path->slots[0] == nritems) |
| 5656 | path->slots[0]--; |
| 5657 | |
| 5658 | btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); |
| 5659 | if (found_key.objectid < min_objectid) |
| 5660 | break; |
| 5661 | if (found_key.type == type) |
| 5662 | return 0; |
| 5663 | if (found_key.objectid == min_objectid && |
| 5664 | found_key.type < type) |
| 5665 | break; |
| 5666 | } |
| 5667 | return 1; |
| 5668 | } |