| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Copyright (C) 2007,2008 Oracle. All rights reserved. |
| 4 | */ |
| 5 | |
| 6 | #include <linux/sched.h> |
| 7 | #include <linux/slab.h> |
| 8 | #include <linux/rbtree.h> |
| 9 | #include <linux/mm.h> |
| 10 | #include <linux/error-injection.h> |
| 11 | #include "ctree.h" |
| 12 | #include "disk-io.h" |
| 13 | #include "transaction.h" |
| 14 | #include "print-tree.h" |
| 15 | #include "locking.h" |
| 16 | #include "volumes.h" |
| 17 | #include "qgroup.h" |
| 18 | #include "tree-mod-log.h" |
| 19 | |
| 20 | static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
| 21 | *root, struct btrfs_path *path, int level); |
| 22 | static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 23 | const struct btrfs_key *ins_key, struct btrfs_path *path, |
| 24 | int data_size, int extend); |
| 25 | static int push_node_left(struct btrfs_trans_handle *trans, |
| 26 | struct extent_buffer *dst, |
| 27 | struct extent_buffer *src, int empty); |
| 28 | static int balance_node_right(struct btrfs_trans_handle *trans, |
| 29 | struct extent_buffer *dst_buf, |
| 30 | struct extent_buffer *src_buf); |
| 31 | static void del_ptr(struct btrfs_root *root, struct btrfs_path *path, |
| 32 | int level, int slot); |
| 33 | |
| 34 | static const struct btrfs_csums { |
| 35 | u16 size; |
| 36 | const char name[10]; |
| 37 | const char driver[12]; |
| 38 | } btrfs_csums[] = { |
| 39 | [BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" }, |
| 40 | [BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" }, |
| 41 | [BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" }, |
| 42 | [BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b", |
| 43 | .driver = "blake2b-256" }, |
| 44 | }; |
| 45 | |
| 46 | int btrfs_super_csum_size(const struct btrfs_super_block *s) |
| 47 | { |
| 48 | u16 t = btrfs_super_csum_type(s); |
| 49 | /* |
| 50 | * csum type is validated at mount time |
| 51 | */ |
| 52 | return btrfs_csums[t].size; |
| 53 | } |
| 54 | |
| 55 | const char *btrfs_super_csum_name(u16 csum_type) |
| 56 | { |
| 57 | /* csum type is validated at mount time */ |
| 58 | return btrfs_csums[csum_type].name; |
| 59 | } |
| 60 | |
| 61 | /* |
| 62 | * Return driver name if defined, otherwise the name that's also a valid driver |
| 63 | * name |
| 64 | */ |
| 65 | const char *btrfs_super_csum_driver(u16 csum_type) |
| 66 | { |
| 67 | /* csum type is validated at mount time */ |
| 68 | return btrfs_csums[csum_type].driver[0] ? |
| 69 | btrfs_csums[csum_type].driver : |
| 70 | btrfs_csums[csum_type].name; |
| 71 | } |
| 72 | |
| 73 | size_t __attribute_const__ btrfs_get_num_csums(void) |
| 74 | { |
| 75 | return ARRAY_SIZE(btrfs_csums); |
| 76 | } |
| 77 | |
| 78 | struct btrfs_path *btrfs_alloc_path(void) |
| 79 | { |
| 80 | return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); |
| 81 | } |
| 82 | |
| 83 | /* this also releases the path */ |
| 84 | void btrfs_free_path(struct btrfs_path *p) |
| 85 | { |
| 86 | if (!p) |
| 87 | return; |
| 88 | btrfs_release_path(p); |
| 89 | kmem_cache_free(btrfs_path_cachep, p); |
| 90 | } |
| 91 | |
| 92 | /* |
| 93 | * path release drops references on the extent buffers in the path |
| 94 | * and it drops any locks held by this path |
| 95 | * |
| 96 | * It is safe to call this on paths that no locks or extent buffers held. |
| 97 | */ |
| 98 | noinline void btrfs_release_path(struct btrfs_path *p) |
| 99 | { |
| 100 | int i; |
| 101 | |
| 102 | for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
| 103 | p->slots[i] = 0; |
| 104 | if (!p->nodes[i]) |
| 105 | continue; |
| 106 | if (p->locks[i]) { |
| 107 | btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]); |
| 108 | p->locks[i] = 0; |
| 109 | } |
| 110 | free_extent_buffer(p->nodes[i]); |
| 111 | p->nodes[i] = NULL; |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | /* |
| 116 | * safely gets a reference on the root node of a tree. A lock |
| 117 | * is not taken, so a concurrent writer may put a different node |
| 118 | * at the root of the tree. See btrfs_lock_root_node for the |
| 119 | * looping required. |
| 120 | * |
| 121 | * The extent buffer returned by this has a reference taken, so |
| 122 | * it won't disappear. It may stop being the root of the tree |
| 123 | * at any time because there are no locks held. |
| 124 | */ |
| 125 | struct extent_buffer *btrfs_root_node(struct btrfs_root *root) |
| 126 | { |
| 127 | struct extent_buffer *eb; |
| 128 | |
| 129 | while (1) { |
| 130 | rcu_read_lock(); |
| 131 | eb = rcu_dereference(root->node); |
| 132 | |
| 133 | /* |
| 134 | * RCU really hurts here, we could free up the root node because |
| 135 | * it was COWed but we may not get the new root node yet so do |
| 136 | * the inc_not_zero dance and if it doesn't work then |
| 137 | * synchronize_rcu and try again. |
| 138 | */ |
| 139 | if (atomic_inc_not_zero(&eb->refs)) { |
| 140 | rcu_read_unlock(); |
| 141 | break; |
| 142 | } |
| 143 | rcu_read_unlock(); |
| 144 | synchronize_rcu(); |
| 145 | } |
| 146 | return eb; |
| 147 | } |
| 148 | |
| 149 | /* |
| 150 | * Cowonly root (not-shareable trees, everything not subvolume or reloc roots), |
| 151 | * just get put onto a simple dirty list. Transaction walks this list to make |
| 152 | * sure they get properly updated on disk. |
| 153 | */ |
| 154 | static void add_root_to_dirty_list(struct btrfs_root *root) |
| 155 | { |
| 156 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 157 | |
| 158 | if (test_bit(BTRFS_ROOT_DIRTY, &root->state) || |
| 159 | !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state)) |
| 160 | return; |
| 161 | |
| 162 | spin_lock(&fs_info->trans_lock); |
| 163 | if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) { |
| 164 | /* Want the extent tree to be the last on the list */ |
| 165 | if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID) |
| 166 | list_move_tail(&root->dirty_list, |
| 167 | &fs_info->dirty_cowonly_roots); |
| 168 | else |
| 169 | list_move(&root->dirty_list, |
| 170 | &fs_info->dirty_cowonly_roots); |
| 171 | } |
| 172 | spin_unlock(&fs_info->trans_lock); |
| 173 | } |
| 174 | |
| 175 | /* |
| 176 | * used by snapshot creation to make a copy of a root for a tree with |
| 177 | * a given objectid. The buffer with the new root node is returned in |
| 178 | * cow_ret, and this func returns zero on success or a negative error code. |
| 179 | */ |
| 180 | int btrfs_copy_root(struct btrfs_trans_handle *trans, |
| 181 | struct btrfs_root *root, |
| 182 | struct extent_buffer *buf, |
| 183 | struct extent_buffer **cow_ret, u64 new_root_objectid) |
| 184 | { |
| 185 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 186 | struct extent_buffer *cow; |
| 187 | int ret = 0; |
| 188 | int level; |
| 189 | struct btrfs_disk_key disk_key; |
| 190 | |
| 191 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| 192 | trans->transid != fs_info->running_transaction->transid); |
| 193 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| 194 | trans->transid != root->last_trans); |
| 195 | |
| 196 | level = btrfs_header_level(buf); |
| 197 | if (level == 0) |
| 198 | btrfs_item_key(buf, &disk_key, 0); |
| 199 | else |
| 200 | btrfs_node_key(buf, &disk_key, 0); |
| 201 | |
| 202 | cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid, |
| 203 | &disk_key, level, buf->start, 0, |
| 204 | BTRFS_NESTING_NEW_ROOT); |
| 205 | if (IS_ERR(cow)) |
| 206 | return PTR_ERR(cow); |
| 207 | |
| 208 | copy_extent_buffer_full(cow, buf); |
| 209 | btrfs_set_header_bytenr(cow, cow->start); |
| 210 | btrfs_set_header_generation(cow, trans->transid); |
| 211 | btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
| 212 | btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
| 213 | BTRFS_HEADER_FLAG_RELOC); |
| 214 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
| 215 | btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
| 216 | else |
| 217 | btrfs_set_header_owner(cow, new_root_objectid); |
| 218 | |
| 219 | write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); |
| 220 | |
| 221 | WARN_ON(btrfs_header_generation(buf) > trans->transid); |
| 222 | if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
| 223 | ret = btrfs_inc_ref(trans, root, cow, 1); |
| 224 | else |
| 225 | ret = btrfs_inc_ref(trans, root, cow, 0); |
| 226 | if (ret) { |
| 227 | btrfs_tree_unlock(cow); |
| 228 | free_extent_buffer(cow); |
| 229 | btrfs_abort_transaction(trans, ret); |
| 230 | return ret; |
| 231 | } |
| 232 | |
| 233 | btrfs_mark_buffer_dirty(cow); |
| 234 | *cow_ret = cow; |
| 235 | return 0; |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * check if the tree block can be shared by multiple trees |
| 240 | */ |
| 241 | int btrfs_block_can_be_shared(struct btrfs_root *root, |
| 242 | struct extent_buffer *buf) |
| 243 | { |
| 244 | /* |
| 245 | * Tree blocks not in shareable trees and tree roots are never shared. |
| 246 | * If a block was allocated after the last snapshot and the block was |
| 247 | * not allocated by tree relocation, we know the block is not shared. |
| 248 | */ |
| 249 | if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| 250 | buf != root->node && buf != root->commit_root && |
| 251 | (btrfs_header_generation(buf) <= |
| 252 | btrfs_root_last_snapshot(&root->root_item) || |
| 253 | btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) |
| 254 | return 1; |
| 255 | |
| 256 | return 0; |
| 257 | } |
| 258 | |
| 259 | static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, |
| 260 | struct btrfs_root *root, |
| 261 | struct extent_buffer *buf, |
| 262 | struct extent_buffer *cow, |
| 263 | int *last_ref) |
| 264 | { |
| 265 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 266 | u64 refs; |
| 267 | u64 owner; |
| 268 | u64 flags; |
| 269 | u64 new_flags = 0; |
| 270 | int ret; |
| 271 | |
| 272 | /* |
| 273 | * Backrefs update rules: |
| 274 | * |
| 275 | * Always use full backrefs for extent pointers in tree block |
| 276 | * allocated by tree relocation. |
| 277 | * |
| 278 | * If a shared tree block is no longer referenced by its owner |
| 279 | * tree (btrfs_header_owner(buf) == root->root_key.objectid), |
| 280 | * use full backrefs for extent pointers in tree block. |
| 281 | * |
| 282 | * If a tree block is been relocating |
| 283 | * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID), |
| 284 | * use full backrefs for extent pointers in tree block. |
| 285 | * The reason for this is some operations (such as drop tree) |
| 286 | * are only allowed for blocks use full backrefs. |
| 287 | */ |
| 288 | |
| 289 | if (btrfs_block_can_be_shared(root, buf)) { |
| 290 | ret = btrfs_lookup_extent_info(trans, fs_info, buf->start, |
| 291 | btrfs_header_level(buf), 1, |
| 292 | &refs, &flags); |
| 293 | if (ret) |
| 294 | return ret; |
| 295 | if (refs == 0) { |
| 296 | ret = -EROFS; |
| 297 | btrfs_handle_fs_error(fs_info, ret, NULL); |
| 298 | return ret; |
| 299 | } |
| 300 | } else { |
| 301 | refs = 1; |
| 302 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
| 303 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| 304 | flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; |
| 305 | else |
| 306 | flags = 0; |
| 307 | } |
| 308 | |
| 309 | owner = btrfs_header_owner(buf); |
| 310 | BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID && |
| 311 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); |
| 312 | |
| 313 | if (refs > 1) { |
| 314 | if ((owner == root->root_key.objectid || |
| 315 | root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && |
| 316 | !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { |
| 317 | ret = btrfs_inc_ref(trans, root, buf, 1); |
| 318 | if (ret) |
| 319 | return ret; |
| 320 | |
| 321 | if (root->root_key.objectid == |
| 322 | BTRFS_TREE_RELOC_OBJECTID) { |
| 323 | ret = btrfs_dec_ref(trans, root, buf, 0); |
| 324 | if (ret) |
| 325 | return ret; |
| 326 | ret = btrfs_inc_ref(trans, root, cow, 1); |
| 327 | if (ret) |
| 328 | return ret; |
| 329 | } |
| 330 | new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; |
| 331 | } else { |
| 332 | |
| 333 | if (root->root_key.objectid == |
| 334 | BTRFS_TREE_RELOC_OBJECTID) |
| 335 | ret = btrfs_inc_ref(trans, root, cow, 1); |
| 336 | else |
| 337 | ret = btrfs_inc_ref(trans, root, cow, 0); |
| 338 | if (ret) |
| 339 | return ret; |
| 340 | } |
| 341 | if (new_flags != 0) { |
| 342 | int level = btrfs_header_level(buf); |
| 343 | |
| 344 | ret = btrfs_set_disk_extent_flags(trans, buf, |
| 345 | new_flags, level, 0); |
| 346 | if (ret) |
| 347 | return ret; |
| 348 | } |
| 349 | } else { |
| 350 | if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) { |
| 351 | if (root->root_key.objectid == |
| 352 | BTRFS_TREE_RELOC_OBJECTID) |
| 353 | ret = btrfs_inc_ref(trans, root, cow, 1); |
| 354 | else |
| 355 | ret = btrfs_inc_ref(trans, root, cow, 0); |
| 356 | if (ret) |
| 357 | return ret; |
| 358 | ret = btrfs_dec_ref(trans, root, buf, 1); |
| 359 | if (ret) |
| 360 | return ret; |
| 361 | } |
| 362 | btrfs_clean_tree_block(buf); |
| 363 | *last_ref = 1; |
| 364 | } |
| 365 | return 0; |
| 366 | } |
| 367 | |
| 368 | /* |
| 369 | * does the dirty work in cow of a single block. The parent block (if |
| 370 | * supplied) is updated to point to the new cow copy. The new buffer is marked |
| 371 | * dirty and returned locked. If you modify the block it needs to be marked |
| 372 | * dirty again. |
| 373 | * |
| 374 | * search_start -- an allocation hint for the new block |
| 375 | * |
| 376 | * empty_size -- a hint that you plan on doing more cow. This is the size in |
| 377 | * bytes the allocator should try to find free next to the block it returns. |
| 378 | * This is just a hint and may be ignored by the allocator. |
| 379 | */ |
| 380 | static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, |
| 381 | struct btrfs_root *root, |
| 382 | struct extent_buffer *buf, |
| 383 | struct extent_buffer *parent, int parent_slot, |
| 384 | struct extent_buffer **cow_ret, |
| 385 | u64 search_start, u64 empty_size, |
| 386 | enum btrfs_lock_nesting nest) |
| 387 | { |
| 388 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 389 | struct btrfs_disk_key disk_key; |
| 390 | struct extent_buffer *cow; |
| 391 | int level, ret; |
| 392 | int last_ref = 0; |
| 393 | int unlock_orig = 0; |
| 394 | u64 parent_start = 0; |
| 395 | |
| 396 | if (*cow_ret == buf) |
| 397 | unlock_orig = 1; |
| 398 | |
| 399 | btrfs_assert_tree_write_locked(buf); |
| 400 | |
| 401 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| 402 | trans->transid != fs_info->running_transaction->transid); |
| 403 | WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| 404 | trans->transid != root->last_trans); |
| 405 | |
| 406 | level = btrfs_header_level(buf); |
| 407 | |
| 408 | if (level == 0) |
| 409 | btrfs_item_key(buf, &disk_key, 0); |
| 410 | else |
| 411 | btrfs_node_key(buf, &disk_key, 0); |
| 412 | |
| 413 | if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent) |
| 414 | parent_start = parent->start; |
| 415 | |
| 416 | cow = btrfs_alloc_tree_block(trans, root, parent_start, |
| 417 | root->root_key.objectid, &disk_key, level, |
| 418 | search_start, empty_size, nest); |
| 419 | if (IS_ERR(cow)) |
| 420 | return PTR_ERR(cow); |
| 421 | |
| 422 | /* cow is set to blocking by btrfs_init_new_buffer */ |
| 423 | |
| 424 | copy_extent_buffer_full(cow, buf); |
| 425 | btrfs_set_header_bytenr(cow, cow->start); |
| 426 | btrfs_set_header_generation(cow, trans->transid); |
| 427 | btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
| 428 | btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
| 429 | BTRFS_HEADER_FLAG_RELOC); |
| 430 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
| 431 | btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
| 432 | else |
| 433 | btrfs_set_header_owner(cow, root->root_key.objectid); |
| 434 | |
| 435 | write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); |
| 436 | |
| 437 | ret = update_ref_for_cow(trans, root, buf, cow, &last_ref); |
| 438 | if (ret) { |
| 439 | btrfs_tree_unlock(cow); |
| 440 | free_extent_buffer(cow); |
| 441 | btrfs_abort_transaction(trans, ret); |
| 442 | return ret; |
| 443 | } |
| 444 | |
| 445 | if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { |
| 446 | ret = btrfs_reloc_cow_block(trans, root, buf, cow); |
| 447 | if (ret) { |
| 448 | btrfs_tree_unlock(cow); |
| 449 | free_extent_buffer(cow); |
| 450 | btrfs_abort_transaction(trans, ret); |
| 451 | return ret; |
| 452 | } |
| 453 | } |
| 454 | |
| 455 | if (buf == root->node) { |
| 456 | WARN_ON(parent && parent != buf); |
| 457 | if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
| 458 | btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| 459 | parent_start = buf->start; |
| 460 | |
| 461 | atomic_inc(&cow->refs); |
| 462 | ret = btrfs_tree_mod_log_insert_root(root->node, cow, true); |
| 463 | BUG_ON(ret < 0); |
| 464 | rcu_assign_pointer(root->node, cow); |
| 465 | |
| 466 | btrfs_free_tree_block(trans, btrfs_root_id(root), buf, |
| 467 | parent_start, last_ref); |
| 468 | free_extent_buffer(buf); |
| 469 | add_root_to_dirty_list(root); |
| 470 | } else { |
| 471 | WARN_ON(trans->transid != btrfs_header_generation(parent)); |
| 472 | btrfs_tree_mod_log_insert_key(parent, parent_slot, |
| 473 | BTRFS_MOD_LOG_KEY_REPLACE, GFP_NOFS); |
| 474 | btrfs_set_node_blockptr(parent, parent_slot, |
| 475 | cow->start); |
| 476 | btrfs_set_node_ptr_generation(parent, parent_slot, |
| 477 | trans->transid); |
| 478 | btrfs_mark_buffer_dirty(parent); |
| 479 | if (last_ref) { |
| 480 | ret = btrfs_tree_mod_log_free_eb(buf); |
| 481 | if (ret) { |
| 482 | btrfs_tree_unlock(cow); |
| 483 | free_extent_buffer(cow); |
| 484 | btrfs_abort_transaction(trans, ret); |
| 485 | return ret; |
| 486 | } |
| 487 | } |
| 488 | btrfs_free_tree_block(trans, btrfs_root_id(root), buf, |
| 489 | parent_start, last_ref); |
| 490 | } |
| 491 | if (unlock_orig) |
| 492 | btrfs_tree_unlock(buf); |
| 493 | free_extent_buffer_stale(buf); |
| 494 | btrfs_mark_buffer_dirty(cow); |
| 495 | *cow_ret = cow; |
| 496 | return 0; |
| 497 | } |
| 498 | |
| 499 | static inline int should_cow_block(struct btrfs_trans_handle *trans, |
| 500 | struct btrfs_root *root, |
| 501 | struct extent_buffer *buf) |
| 502 | { |
| 503 | if (btrfs_is_testing(root->fs_info)) |
| 504 | return 0; |
| 505 | |
| 506 | /* Ensure we can see the FORCE_COW bit */ |
| 507 | smp_mb__before_atomic(); |
| 508 | |
| 509 | /* |
| 510 | * We do not need to cow a block if |
| 511 | * 1) this block is not created or changed in this transaction; |
| 512 | * 2) this block does not belong to TREE_RELOC tree; |
| 513 | * 3) the root is not forced COW. |
| 514 | * |
| 515 | * What is forced COW: |
| 516 | * when we create snapshot during committing the transaction, |
| 517 | * after we've finished copying src root, we must COW the shared |
| 518 | * block to ensure the metadata consistency. |
| 519 | */ |
| 520 | if (btrfs_header_generation(buf) == trans->transid && |
| 521 | !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) && |
| 522 | !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && |
| 523 | btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) && |
| 524 | !test_bit(BTRFS_ROOT_FORCE_COW, &root->state)) |
| 525 | return 0; |
| 526 | return 1; |
| 527 | } |
| 528 | |
| 529 | /* |
| 530 | * cows a single block, see __btrfs_cow_block for the real work. |
| 531 | * This version of it has extra checks so that a block isn't COWed more than |
| 532 | * once per transaction, as long as it hasn't been written yet |
| 533 | */ |
| 534 | noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, |
| 535 | struct btrfs_root *root, struct extent_buffer *buf, |
| 536 | struct extent_buffer *parent, int parent_slot, |
| 537 | struct extent_buffer **cow_ret, |
| 538 | enum btrfs_lock_nesting nest) |
| 539 | { |
| 540 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 541 | u64 search_start; |
| 542 | int ret; |
| 543 | |
| 544 | if (test_bit(BTRFS_ROOT_DELETING, &root->state)) |
| 545 | btrfs_err(fs_info, |
| 546 | "COW'ing blocks on a fs root that's being dropped"); |
| 547 | |
| 548 | if (trans->transaction != fs_info->running_transaction) |
| 549 | WARN(1, KERN_CRIT "trans %llu running %llu\n", |
| 550 | trans->transid, |
| 551 | fs_info->running_transaction->transid); |
| 552 | |
| 553 | if (trans->transid != fs_info->generation) |
| 554 | WARN(1, KERN_CRIT "trans %llu running %llu\n", |
| 555 | trans->transid, fs_info->generation); |
| 556 | |
| 557 | if (!should_cow_block(trans, root, buf)) { |
| 558 | *cow_ret = buf; |
| 559 | return 0; |
| 560 | } |
| 561 | |
| 562 | search_start = buf->start & ~((u64)SZ_1G - 1); |
| 563 | |
| 564 | /* |
| 565 | * Before CoWing this block for later modification, check if it's |
| 566 | * the subtree root and do the delayed subtree trace if needed. |
| 567 | * |
| 568 | * Also We don't care about the error, as it's handled internally. |
| 569 | */ |
| 570 | btrfs_qgroup_trace_subtree_after_cow(trans, root, buf); |
| 571 | ret = __btrfs_cow_block(trans, root, buf, parent, |
| 572 | parent_slot, cow_ret, search_start, 0, nest); |
| 573 | |
| 574 | trace_btrfs_cow_block(root, buf, *cow_ret); |
| 575 | |
| 576 | return ret; |
| 577 | } |
| 578 | ALLOW_ERROR_INJECTION(btrfs_cow_block, ERRNO); |
| 579 | |
| 580 | /* |
| 581 | * helper function for defrag to decide if two blocks pointed to by a |
| 582 | * node are actually close by |
| 583 | */ |
| 584 | static int close_blocks(u64 blocknr, u64 other, u32 blocksize) |
| 585 | { |
| 586 | if (blocknr < other && other - (blocknr + blocksize) < 32768) |
| 587 | return 1; |
| 588 | if (blocknr > other && blocknr - (other + blocksize) < 32768) |
| 589 | return 1; |
| 590 | return 0; |
| 591 | } |
| 592 | |
| 593 | #ifdef __LITTLE_ENDIAN |
| 594 | |
| 595 | /* |
| 596 | * Compare two keys, on little-endian the disk order is same as CPU order and |
| 597 | * we can avoid the conversion. |
| 598 | */ |
| 599 | static int comp_keys(const struct btrfs_disk_key *disk_key, |
| 600 | const struct btrfs_key *k2) |
| 601 | { |
| 602 | const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key; |
| 603 | |
| 604 | return btrfs_comp_cpu_keys(k1, k2); |
| 605 | } |
| 606 | |
| 607 | #else |
| 608 | |
| 609 | /* |
| 610 | * compare two keys in a memcmp fashion |
| 611 | */ |
| 612 | static int comp_keys(const struct btrfs_disk_key *disk, |
| 613 | const struct btrfs_key *k2) |
| 614 | { |
| 615 | struct btrfs_key k1; |
| 616 | |
| 617 | btrfs_disk_key_to_cpu(&k1, disk); |
| 618 | |
| 619 | return btrfs_comp_cpu_keys(&k1, k2); |
| 620 | } |
| 621 | #endif |
| 622 | |
| 623 | /* |
| 624 | * same as comp_keys only with two btrfs_key's |
| 625 | */ |
| 626 | int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2) |
| 627 | { |
| 628 | if (k1->objectid > k2->objectid) |
| 629 | return 1; |
| 630 | if (k1->objectid < k2->objectid) |
| 631 | return -1; |
| 632 | if (k1->type > k2->type) |
| 633 | return 1; |
| 634 | if (k1->type < k2->type) |
| 635 | return -1; |
| 636 | if (k1->offset > k2->offset) |
| 637 | return 1; |
| 638 | if (k1->offset < k2->offset) |
| 639 | return -1; |
| 640 | return 0; |
| 641 | } |
| 642 | |
| 643 | /* |
| 644 | * this is used by the defrag code to go through all the |
| 645 | * leaves pointed to by a node and reallocate them so that |
| 646 | * disk order is close to key order |
| 647 | */ |
| 648 | int btrfs_realloc_node(struct btrfs_trans_handle *trans, |
| 649 | struct btrfs_root *root, struct extent_buffer *parent, |
| 650 | int start_slot, u64 *last_ret, |
| 651 | struct btrfs_key *progress) |
| 652 | { |
| 653 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 654 | struct extent_buffer *cur; |
| 655 | u64 blocknr; |
| 656 | u64 search_start = *last_ret; |
| 657 | u64 last_block = 0; |
| 658 | u64 other; |
| 659 | u32 parent_nritems; |
| 660 | int end_slot; |
| 661 | int i; |
| 662 | int err = 0; |
| 663 | u32 blocksize; |
| 664 | int progress_passed = 0; |
| 665 | struct btrfs_disk_key disk_key; |
| 666 | |
| 667 | WARN_ON(trans->transaction != fs_info->running_transaction); |
| 668 | WARN_ON(trans->transid != fs_info->generation); |
| 669 | |
| 670 | parent_nritems = btrfs_header_nritems(parent); |
| 671 | blocksize = fs_info->nodesize; |
| 672 | end_slot = parent_nritems - 1; |
| 673 | |
| 674 | if (parent_nritems <= 1) |
| 675 | return 0; |
| 676 | |
| 677 | for (i = start_slot; i <= end_slot; i++) { |
| 678 | int close = 1; |
| 679 | |
| 680 | btrfs_node_key(parent, &disk_key, i); |
| 681 | if (!progress_passed && comp_keys(&disk_key, progress) < 0) |
| 682 | continue; |
| 683 | |
| 684 | progress_passed = 1; |
| 685 | blocknr = btrfs_node_blockptr(parent, i); |
| 686 | if (last_block == 0) |
| 687 | last_block = blocknr; |
| 688 | |
| 689 | if (i > 0) { |
| 690 | other = btrfs_node_blockptr(parent, i - 1); |
| 691 | close = close_blocks(blocknr, other, blocksize); |
| 692 | } |
| 693 | if (!close && i < end_slot) { |
| 694 | other = btrfs_node_blockptr(parent, i + 1); |
| 695 | close = close_blocks(blocknr, other, blocksize); |
| 696 | } |
| 697 | if (close) { |
| 698 | last_block = blocknr; |
| 699 | continue; |
| 700 | } |
| 701 | |
| 702 | cur = btrfs_read_node_slot(parent, i); |
| 703 | if (IS_ERR(cur)) |
| 704 | return PTR_ERR(cur); |
| 705 | if (search_start == 0) |
| 706 | search_start = last_block; |
| 707 | |
| 708 | btrfs_tree_lock(cur); |
| 709 | err = __btrfs_cow_block(trans, root, cur, parent, i, |
| 710 | &cur, search_start, |
| 711 | min(16 * blocksize, |
| 712 | (end_slot - i) * blocksize), |
| 713 | BTRFS_NESTING_COW); |
| 714 | if (err) { |
| 715 | btrfs_tree_unlock(cur); |
| 716 | free_extent_buffer(cur); |
| 717 | break; |
| 718 | } |
| 719 | search_start = cur->start; |
| 720 | last_block = cur->start; |
| 721 | *last_ret = search_start; |
| 722 | btrfs_tree_unlock(cur); |
| 723 | free_extent_buffer(cur); |
| 724 | } |
| 725 | return err; |
| 726 | } |
| 727 | |
| 728 | /* |
| 729 | * Search for a key in the given extent_buffer. |
| 730 | * |
| 731 | * The lower boundary for the search is specified by the slot number @low. Use a |
| 732 | * value of 0 to search over the whole extent buffer. |
| 733 | * |
| 734 | * The slot in the extent buffer is returned via @slot. If the key exists in the |
| 735 | * extent buffer, then @slot will point to the slot where the key is, otherwise |
| 736 | * it points to the slot where you would insert the key. |
| 737 | * |
| 738 | * Slot may point to the total number of items (i.e. one position beyond the last |
| 739 | * key) if the key is bigger than the last key in the extent buffer. |
| 740 | */ |
| 741 | static noinline int generic_bin_search(struct extent_buffer *eb, int low, |
| 742 | const struct btrfs_key *key, int *slot) |
| 743 | { |
| 744 | unsigned long p; |
| 745 | int item_size; |
| 746 | int high = btrfs_header_nritems(eb); |
| 747 | int ret; |
| 748 | const int key_size = sizeof(struct btrfs_disk_key); |
| 749 | |
| 750 | if (low > high) { |
| 751 | btrfs_err(eb->fs_info, |
| 752 | "%s: low (%d) > high (%d) eb %llu owner %llu level %d", |
| 753 | __func__, low, high, eb->start, |
| 754 | btrfs_header_owner(eb), btrfs_header_level(eb)); |
| 755 | return -EINVAL; |
| 756 | } |
| 757 | |
| 758 | if (btrfs_header_level(eb) == 0) { |
| 759 | p = offsetof(struct btrfs_leaf, items); |
| 760 | item_size = sizeof(struct btrfs_item); |
| 761 | } else { |
| 762 | p = offsetof(struct btrfs_node, ptrs); |
| 763 | item_size = sizeof(struct btrfs_key_ptr); |
| 764 | } |
| 765 | |
| 766 | while (low < high) { |
| 767 | unsigned long oip; |
| 768 | unsigned long offset; |
| 769 | struct btrfs_disk_key *tmp; |
| 770 | struct btrfs_disk_key unaligned; |
| 771 | int mid; |
| 772 | |
| 773 | mid = (low + high) / 2; |
| 774 | offset = p + mid * item_size; |
| 775 | oip = offset_in_page(offset); |
| 776 | |
| 777 | if (oip + key_size <= PAGE_SIZE) { |
| 778 | const unsigned long idx = get_eb_page_index(offset); |
| 779 | char *kaddr = page_address(eb->pages[idx]); |
| 780 | |
| 781 | oip = get_eb_offset_in_page(eb, offset); |
| 782 | tmp = (struct btrfs_disk_key *)(kaddr + oip); |
| 783 | } else { |
| 784 | read_extent_buffer(eb, &unaligned, offset, key_size); |
| 785 | tmp = &unaligned; |
| 786 | } |
| 787 | |
| 788 | ret = comp_keys(tmp, key); |
| 789 | |
| 790 | if (ret < 0) |
| 791 | low = mid + 1; |
| 792 | else if (ret > 0) |
| 793 | high = mid; |
| 794 | else { |
| 795 | *slot = mid; |
| 796 | return 0; |
| 797 | } |
| 798 | } |
| 799 | *slot = low; |
| 800 | return 1; |
| 801 | } |
| 802 | |
| 803 | /* |
| 804 | * Simple binary search on an extent buffer. Works for both leaves and nodes, and |
| 805 | * always searches over the whole range of keys (slot 0 to slot 'nritems - 1'). |
| 806 | */ |
| 807 | int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key, |
| 808 | int *slot) |
| 809 | { |
| 810 | return generic_bin_search(eb, 0, key, slot); |
| 811 | } |
| 812 | |
| 813 | static void root_add_used(struct btrfs_root *root, u32 size) |
| 814 | { |
| 815 | spin_lock(&root->accounting_lock); |
| 816 | btrfs_set_root_used(&root->root_item, |
| 817 | btrfs_root_used(&root->root_item) + size); |
| 818 | spin_unlock(&root->accounting_lock); |
| 819 | } |
| 820 | |
| 821 | static void root_sub_used(struct btrfs_root *root, u32 size) |
| 822 | { |
| 823 | spin_lock(&root->accounting_lock); |
| 824 | btrfs_set_root_used(&root->root_item, |
| 825 | btrfs_root_used(&root->root_item) - size); |
| 826 | spin_unlock(&root->accounting_lock); |
| 827 | } |
| 828 | |
| 829 | /* given a node and slot number, this reads the blocks it points to. The |
| 830 | * extent buffer is returned with a reference taken (but unlocked). |
| 831 | */ |
| 832 | struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent, |
| 833 | int slot) |
| 834 | { |
| 835 | int level = btrfs_header_level(parent); |
| 836 | struct extent_buffer *eb; |
| 837 | struct btrfs_key first_key; |
| 838 | |
| 839 | if (slot < 0 || slot >= btrfs_header_nritems(parent)) |
| 840 | return ERR_PTR(-ENOENT); |
| 841 | |
| 842 | BUG_ON(level == 0); |
| 843 | |
| 844 | btrfs_node_key_to_cpu(parent, &first_key, slot); |
| 845 | eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot), |
| 846 | btrfs_header_owner(parent), |
| 847 | btrfs_node_ptr_generation(parent, slot), |
| 848 | level - 1, &first_key); |
| 849 | if (IS_ERR(eb)) |
| 850 | return eb; |
| 851 | if (!extent_buffer_uptodate(eb)) { |
| 852 | free_extent_buffer(eb); |
| 853 | return ERR_PTR(-EIO); |
| 854 | } |
| 855 | |
| 856 | return eb; |
| 857 | } |
| 858 | |
| 859 | /* |
| 860 | * node level balancing, used to make sure nodes are in proper order for |
| 861 | * item deletion. We balance from the top down, so we have to make sure |
| 862 | * that a deletion won't leave an node completely empty later on. |
| 863 | */ |
| 864 | static noinline int balance_level(struct btrfs_trans_handle *trans, |
| 865 | struct btrfs_root *root, |
| 866 | struct btrfs_path *path, int level) |
| 867 | { |
| 868 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 869 | struct extent_buffer *right = NULL; |
| 870 | struct extent_buffer *mid; |
| 871 | struct extent_buffer *left = NULL; |
| 872 | struct extent_buffer *parent = NULL; |
| 873 | int ret = 0; |
| 874 | int wret; |
| 875 | int pslot; |
| 876 | int orig_slot = path->slots[level]; |
| 877 | u64 orig_ptr; |
| 878 | |
| 879 | ASSERT(level > 0); |
| 880 | |
| 881 | mid = path->nodes[level]; |
| 882 | |
| 883 | WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK); |
| 884 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
| 885 | |
| 886 | orig_ptr = btrfs_node_blockptr(mid, orig_slot); |
| 887 | |
| 888 | if (level < BTRFS_MAX_LEVEL - 1) { |
| 889 | parent = path->nodes[level + 1]; |
| 890 | pslot = path->slots[level + 1]; |
| 891 | } |
| 892 | |
| 893 | /* |
| 894 | * deal with the case where there is only one pointer in the root |
| 895 | * by promoting the node below to a root |
| 896 | */ |
| 897 | if (!parent) { |
| 898 | struct extent_buffer *child; |
| 899 | |
| 900 | if (btrfs_header_nritems(mid) != 1) |
| 901 | return 0; |
| 902 | |
| 903 | /* promote the child to a root */ |
| 904 | child = btrfs_read_node_slot(mid, 0); |
| 905 | if (IS_ERR(child)) { |
| 906 | ret = PTR_ERR(child); |
| 907 | btrfs_handle_fs_error(fs_info, ret, NULL); |
| 908 | goto enospc; |
| 909 | } |
| 910 | |
| 911 | btrfs_tree_lock(child); |
| 912 | ret = btrfs_cow_block(trans, root, child, mid, 0, &child, |
| 913 | BTRFS_NESTING_COW); |
| 914 | if (ret) { |
| 915 | btrfs_tree_unlock(child); |
| 916 | free_extent_buffer(child); |
| 917 | goto enospc; |
| 918 | } |
| 919 | |
| 920 | ret = btrfs_tree_mod_log_insert_root(root->node, child, true); |
| 921 | BUG_ON(ret < 0); |
| 922 | rcu_assign_pointer(root->node, child); |
| 923 | |
| 924 | add_root_to_dirty_list(root); |
| 925 | btrfs_tree_unlock(child); |
| 926 | |
| 927 | path->locks[level] = 0; |
| 928 | path->nodes[level] = NULL; |
| 929 | btrfs_clean_tree_block(mid); |
| 930 | btrfs_tree_unlock(mid); |
| 931 | /* once for the path */ |
| 932 | free_extent_buffer(mid); |
| 933 | |
| 934 | root_sub_used(root, mid->len); |
| 935 | btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1); |
| 936 | /* once for the root ptr */ |
| 937 | free_extent_buffer_stale(mid); |
| 938 | return 0; |
| 939 | } |
| 940 | if (btrfs_header_nritems(mid) > |
| 941 | BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4) |
| 942 | return 0; |
| 943 | |
| 944 | left = btrfs_read_node_slot(parent, pslot - 1); |
| 945 | if (IS_ERR(left)) |
| 946 | left = NULL; |
| 947 | |
| 948 | if (left) { |
| 949 | __btrfs_tree_lock(left, BTRFS_NESTING_LEFT); |
| 950 | wret = btrfs_cow_block(trans, root, left, |
| 951 | parent, pslot - 1, &left, |
| 952 | BTRFS_NESTING_LEFT_COW); |
| 953 | if (wret) { |
| 954 | ret = wret; |
| 955 | goto enospc; |
| 956 | } |
| 957 | } |
| 958 | |
| 959 | right = btrfs_read_node_slot(parent, pslot + 1); |
| 960 | if (IS_ERR(right)) |
| 961 | right = NULL; |
| 962 | |
| 963 | if (right) { |
| 964 | __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); |
| 965 | wret = btrfs_cow_block(trans, root, right, |
| 966 | parent, pslot + 1, &right, |
| 967 | BTRFS_NESTING_RIGHT_COW); |
| 968 | if (wret) { |
| 969 | ret = wret; |
| 970 | goto enospc; |
| 971 | } |
| 972 | } |
| 973 | |
| 974 | /* first, try to make some room in the middle buffer */ |
| 975 | if (left) { |
| 976 | orig_slot += btrfs_header_nritems(left); |
| 977 | wret = push_node_left(trans, left, mid, 1); |
| 978 | if (wret < 0) |
| 979 | ret = wret; |
| 980 | } |
| 981 | |
| 982 | /* |
| 983 | * then try to empty the right most buffer into the middle |
| 984 | */ |
| 985 | if (right) { |
| 986 | wret = push_node_left(trans, mid, right, 1); |
| 987 | if (wret < 0 && wret != -ENOSPC) |
| 988 | ret = wret; |
| 989 | if (btrfs_header_nritems(right) == 0) { |
| 990 | btrfs_clean_tree_block(right); |
| 991 | btrfs_tree_unlock(right); |
| 992 | del_ptr(root, path, level + 1, pslot + 1); |
| 993 | root_sub_used(root, right->len); |
| 994 | btrfs_free_tree_block(trans, btrfs_root_id(root), right, |
| 995 | 0, 1); |
| 996 | free_extent_buffer_stale(right); |
| 997 | right = NULL; |
| 998 | } else { |
| 999 | struct btrfs_disk_key right_key; |
| 1000 | btrfs_node_key(right, &right_key, 0); |
| 1001 | ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1, |
| 1002 | BTRFS_MOD_LOG_KEY_REPLACE, GFP_NOFS); |
| 1003 | BUG_ON(ret < 0); |
| 1004 | btrfs_set_node_key(parent, &right_key, pslot + 1); |
| 1005 | btrfs_mark_buffer_dirty(parent); |
| 1006 | } |
| 1007 | } |
| 1008 | if (btrfs_header_nritems(mid) == 1) { |
| 1009 | /* |
| 1010 | * we're not allowed to leave a node with one item in the |
| 1011 | * tree during a delete. A deletion from lower in the tree |
| 1012 | * could try to delete the only pointer in this node. |
| 1013 | * So, pull some keys from the left. |
| 1014 | * There has to be a left pointer at this point because |
| 1015 | * otherwise we would have pulled some pointers from the |
| 1016 | * right |
| 1017 | */ |
| 1018 | if (!left) { |
| 1019 | ret = -EROFS; |
| 1020 | btrfs_handle_fs_error(fs_info, ret, NULL); |
| 1021 | goto enospc; |
| 1022 | } |
| 1023 | wret = balance_node_right(trans, mid, left); |
| 1024 | if (wret < 0) { |
| 1025 | ret = wret; |
| 1026 | goto enospc; |
| 1027 | } |
| 1028 | if (wret == 1) { |
| 1029 | wret = push_node_left(trans, left, mid, 1); |
| 1030 | if (wret < 0) |
| 1031 | ret = wret; |
| 1032 | } |
| 1033 | BUG_ON(wret == 1); |
| 1034 | } |
| 1035 | if (btrfs_header_nritems(mid) == 0) { |
| 1036 | btrfs_clean_tree_block(mid); |
| 1037 | btrfs_tree_unlock(mid); |
| 1038 | del_ptr(root, path, level + 1, pslot); |
| 1039 | root_sub_used(root, mid->len); |
| 1040 | btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1); |
| 1041 | free_extent_buffer_stale(mid); |
| 1042 | mid = NULL; |
| 1043 | } else { |
| 1044 | /* update the parent key to reflect our changes */ |
| 1045 | struct btrfs_disk_key mid_key; |
| 1046 | btrfs_node_key(mid, &mid_key, 0); |
| 1047 | ret = btrfs_tree_mod_log_insert_key(parent, pslot, |
| 1048 | BTRFS_MOD_LOG_KEY_REPLACE, GFP_NOFS); |
| 1049 | BUG_ON(ret < 0); |
| 1050 | btrfs_set_node_key(parent, &mid_key, pslot); |
| 1051 | btrfs_mark_buffer_dirty(parent); |
| 1052 | } |
| 1053 | |
| 1054 | /* update the path */ |
| 1055 | if (left) { |
| 1056 | if (btrfs_header_nritems(left) > orig_slot) { |
| 1057 | atomic_inc(&left->refs); |
| 1058 | /* left was locked after cow */ |
| 1059 | path->nodes[level] = left; |
| 1060 | path->slots[level + 1] -= 1; |
| 1061 | path->slots[level] = orig_slot; |
| 1062 | if (mid) { |
| 1063 | btrfs_tree_unlock(mid); |
| 1064 | free_extent_buffer(mid); |
| 1065 | } |
| 1066 | } else { |
| 1067 | orig_slot -= btrfs_header_nritems(left); |
| 1068 | path->slots[level] = orig_slot; |
| 1069 | } |
| 1070 | } |
| 1071 | /* double check we haven't messed things up */ |
| 1072 | if (orig_ptr != |
| 1073 | btrfs_node_blockptr(path->nodes[level], path->slots[level])) |
| 1074 | BUG(); |
| 1075 | enospc: |
| 1076 | if (right) { |
| 1077 | btrfs_tree_unlock(right); |
| 1078 | free_extent_buffer(right); |
| 1079 | } |
| 1080 | if (left) { |
| 1081 | if (path->nodes[level] != left) |
| 1082 | btrfs_tree_unlock(left); |
| 1083 | free_extent_buffer(left); |
| 1084 | } |
| 1085 | return ret; |
| 1086 | } |
| 1087 | |
| 1088 | /* Node balancing for insertion. Here we only split or push nodes around |
| 1089 | * when they are completely full. This is also done top down, so we |
| 1090 | * have to be pessimistic. |
| 1091 | */ |
| 1092 | static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, |
| 1093 | struct btrfs_root *root, |
| 1094 | struct btrfs_path *path, int level) |
| 1095 | { |
| 1096 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 1097 | struct extent_buffer *right = NULL; |
| 1098 | struct extent_buffer *mid; |
| 1099 | struct extent_buffer *left = NULL; |
| 1100 | struct extent_buffer *parent = NULL; |
| 1101 | int ret = 0; |
| 1102 | int wret; |
| 1103 | int pslot; |
| 1104 | int orig_slot = path->slots[level]; |
| 1105 | |
| 1106 | if (level == 0) |
| 1107 | return 1; |
| 1108 | |
| 1109 | mid = path->nodes[level]; |
| 1110 | WARN_ON(btrfs_header_generation(mid) != trans->transid); |
| 1111 | |
| 1112 | if (level < BTRFS_MAX_LEVEL - 1) { |
| 1113 | parent = path->nodes[level + 1]; |
| 1114 | pslot = path->slots[level + 1]; |
| 1115 | } |
| 1116 | |
| 1117 | if (!parent) |
| 1118 | return 1; |
| 1119 | |
| 1120 | left = btrfs_read_node_slot(parent, pslot - 1); |
| 1121 | if (IS_ERR(left)) |
| 1122 | left = NULL; |
| 1123 | |
| 1124 | /* first, try to make some room in the middle buffer */ |
| 1125 | if (left) { |
| 1126 | u32 left_nr; |
| 1127 | |
| 1128 | __btrfs_tree_lock(left, BTRFS_NESTING_LEFT); |
| 1129 | |
| 1130 | left_nr = btrfs_header_nritems(left); |
| 1131 | if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) { |
| 1132 | wret = 1; |
| 1133 | } else { |
| 1134 | ret = btrfs_cow_block(trans, root, left, parent, |
| 1135 | pslot - 1, &left, |
| 1136 | BTRFS_NESTING_LEFT_COW); |
| 1137 | if (ret) |
| 1138 | wret = 1; |
| 1139 | else { |
| 1140 | wret = push_node_left(trans, left, mid, 0); |
| 1141 | } |
| 1142 | } |
| 1143 | if (wret < 0) |
| 1144 | ret = wret; |
| 1145 | if (wret == 0) { |
| 1146 | struct btrfs_disk_key disk_key; |
| 1147 | orig_slot += left_nr; |
| 1148 | btrfs_node_key(mid, &disk_key, 0); |
| 1149 | ret = btrfs_tree_mod_log_insert_key(parent, pslot, |
| 1150 | BTRFS_MOD_LOG_KEY_REPLACE, GFP_NOFS); |
| 1151 | BUG_ON(ret < 0); |
| 1152 | btrfs_set_node_key(parent, &disk_key, pslot); |
| 1153 | btrfs_mark_buffer_dirty(parent); |
| 1154 | if (btrfs_header_nritems(left) > orig_slot) { |
| 1155 | path->nodes[level] = left; |
| 1156 | path->slots[level + 1] -= 1; |
| 1157 | path->slots[level] = orig_slot; |
| 1158 | btrfs_tree_unlock(mid); |
| 1159 | free_extent_buffer(mid); |
| 1160 | } else { |
| 1161 | orig_slot -= |
| 1162 | btrfs_header_nritems(left); |
| 1163 | path->slots[level] = orig_slot; |
| 1164 | btrfs_tree_unlock(left); |
| 1165 | free_extent_buffer(left); |
| 1166 | } |
| 1167 | return 0; |
| 1168 | } |
| 1169 | btrfs_tree_unlock(left); |
| 1170 | free_extent_buffer(left); |
| 1171 | } |
| 1172 | right = btrfs_read_node_slot(parent, pslot + 1); |
| 1173 | if (IS_ERR(right)) |
| 1174 | right = NULL; |
| 1175 | |
| 1176 | /* |
| 1177 | * then try to empty the right most buffer into the middle |
| 1178 | */ |
| 1179 | if (right) { |
| 1180 | u32 right_nr; |
| 1181 | |
| 1182 | __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); |
| 1183 | |
| 1184 | right_nr = btrfs_header_nritems(right); |
| 1185 | if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) { |
| 1186 | wret = 1; |
| 1187 | } else { |
| 1188 | ret = btrfs_cow_block(trans, root, right, |
| 1189 | parent, pslot + 1, |
| 1190 | &right, BTRFS_NESTING_RIGHT_COW); |
| 1191 | if (ret) |
| 1192 | wret = 1; |
| 1193 | else { |
| 1194 | wret = balance_node_right(trans, right, mid); |
| 1195 | } |
| 1196 | } |
| 1197 | if (wret < 0) |
| 1198 | ret = wret; |
| 1199 | if (wret == 0) { |
| 1200 | struct btrfs_disk_key disk_key; |
| 1201 | |
| 1202 | btrfs_node_key(right, &disk_key, 0); |
| 1203 | ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1, |
| 1204 | BTRFS_MOD_LOG_KEY_REPLACE, GFP_NOFS); |
| 1205 | BUG_ON(ret < 0); |
| 1206 | btrfs_set_node_key(parent, &disk_key, pslot + 1); |
| 1207 | btrfs_mark_buffer_dirty(parent); |
| 1208 | |
| 1209 | if (btrfs_header_nritems(mid) <= orig_slot) { |
| 1210 | path->nodes[level] = right; |
| 1211 | path->slots[level + 1] += 1; |
| 1212 | path->slots[level] = orig_slot - |
| 1213 | btrfs_header_nritems(mid); |
| 1214 | btrfs_tree_unlock(mid); |
| 1215 | free_extent_buffer(mid); |
| 1216 | } else { |
| 1217 | btrfs_tree_unlock(right); |
| 1218 | free_extent_buffer(right); |
| 1219 | } |
| 1220 | return 0; |
| 1221 | } |
| 1222 | btrfs_tree_unlock(right); |
| 1223 | free_extent_buffer(right); |
| 1224 | } |
| 1225 | return 1; |
| 1226 | } |
| 1227 | |
| 1228 | /* |
| 1229 | * readahead one full node of leaves, finding things that are close |
| 1230 | * to the block in 'slot', and triggering ra on them. |
| 1231 | */ |
| 1232 | static void reada_for_search(struct btrfs_fs_info *fs_info, |
| 1233 | struct btrfs_path *path, |
| 1234 | int level, int slot, u64 objectid) |
| 1235 | { |
| 1236 | struct extent_buffer *node; |
| 1237 | struct btrfs_disk_key disk_key; |
| 1238 | u32 nritems; |
| 1239 | u64 search; |
| 1240 | u64 target; |
| 1241 | u64 nread = 0; |
| 1242 | u64 nread_max; |
| 1243 | u32 nr; |
| 1244 | u32 blocksize; |
| 1245 | u32 nscan = 0; |
| 1246 | |
| 1247 | if (level != 1 && path->reada != READA_FORWARD_ALWAYS) |
| 1248 | return; |
| 1249 | |
| 1250 | if (!path->nodes[level]) |
| 1251 | return; |
| 1252 | |
| 1253 | node = path->nodes[level]; |
| 1254 | |
| 1255 | /* |
| 1256 | * Since the time between visiting leaves is much shorter than the time |
| 1257 | * between visiting nodes, limit read ahead of nodes to 1, to avoid too |
| 1258 | * much IO at once (possibly random). |
| 1259 | */ |
| 1260 | if (path->reada == READA_FORWARD_ALWAYS) { |
| 1261 | if (level > 1) |
| 1262 | nread_max = node->fs_info->nodesize; |
| 1263 | else |
| 1264 | nread_max = SZ_128K; |
| 1265 | } else { |
| 1266 | nread_max = SZ_64K; |
| 1267 | } |
| 1268 | |
| 1269 | search = btrfs_node_blockptr(node, slot); |
| 1270 | blocksize = fs_info->nodesize; |
| 1271 | if (path->reada != READA_FORWARD_ALWAYS) { |
| 1272 | struct extent_buffer *eb; |
| 1273 | |
| 1274 | eb = find_extent_buffer(fs_info, search); |
| 1275 | if (eb) { |
| 1276 | free_extent_buffer(eb); |
| 1277 | return; |
| 1278 | } |
| 1279 | } |
| 1280 | |
| 1281 | target = search; |
| 1282 | |
| 1283 | nritems = btrfs_header_nritems(node); |
| 1284 | nr = slot; |
| 1285 | |
| 1286 | while (1) { |
| 1287 | if (path->reada == READA_BACK) { |
| 1288 | if (nr == 0) |
| 1289 | break; |
| 1290 | nr--; |
| 1291 | } else if (path->reada == READA_FORWARD || |
| 1292 | path->reada == READA_FORWARD_ALWAYS) { |
| 1293 | nr++; |
| 1294 | if (nr >= nritems) |
| 1295 | break; |
| 1296 | } |
| 1297 | if (path->reada == READA_BACK && objectid) { |
| 1298 | btrfs_node_key(node, &disk_key, nr); |
| 1299 | if (btrfs_disk_key_objectid(&disk_key) != objectid) |
| 1300 | break; |
| 1301 | } |
| 1302 | search = btrfs_node_blockptr(node, nr); |
| 1303 | if (path->reada == READA_FORWARD_ALWAYS || |
| 1304 | (search <= target && target - search <= 65536) || |
| 1305 | (search > target && search - target <= 65536)) { |
| 1306 | btrfs_readahead_node_child(node, nr); |
| 1307 | nread += blocksize; |
| 1308 | } |
| 1309 | nscan++; |
| 1310 | if (nread > nread_max || nscan > 32) |
| 1311 | break; |
| 1312 | } |
| 1313 | } |
| 1314 | |
| 1315 | static noinline void reada_for_balance(struct btrfs_path *path, int level) |
| 1316 | { |
| 1317 | struct extent_buffer *parent; |
| 1318 | int slot; |
| 1319 | int nritems; |
| 1320 | |
| 1321 | parent = path->nodes[level + 1]; |
| 1322 | if (!parent) |
| 1323 | return; |
| 1324 | |
| 1325 | nritems = btrfs_header_nritems(parent); |
| 1326 | slot = path->slots[level + 1]; |
| 1327 | |
| 1328 | if (slot > 0) |
| 1329 | btrfs_readahead_node_child(parent, slot - 1); |
| 1330 | if (slot + 1 < nritems) |
| 1331 | btrfs_readahead_node_child(parent, slot + 1); |
| 1332 | } |
| 1333 | |
| 1334 | |
| 1335 | /* |
| 1336 | * when we walk down the tree, it is usually safe to unlock the higher layers |
| 1337 | * in the tree. The exceptions are when our path goes through slot 0, because |
| 1338 | * operations on the tree might require changing key pointers higher up in the |
| 1339 | * tree. |
| 1340 | * |
| 1341 | * callers might also have set path->keep_locks, which tells this code to keep |
| 1342 | * the lock if the path points to the last slot in the block. This is part of |
| 1343 | * walking through the tree, and selecting the next slot in the higher block. |
| 1344 | * |
| 1345 | * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so |
| 1346 | * if lowest_unlock is 1, level 0 won't be unlocked |
| 1347 | */ |
| 1348 | static noinline void unlock_up(struct btrfs_path *path, int level, |
| 1349 | int lowest_unlock, int min_write_lock_level, |
| 1350 | int *write_lock_level) |
| 1351 | { |
| 1352 | int i; |
| 1353 | int skip_level = level; |
| 1354 | bool check_skip = true; |
| 1355 | |
| 1356 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| 1357 | if (!path->nodes[i]) |
| 1358 | break; |
| 1359 | if (!path->locks[i]) |
| 1360 | break; |
| 1361 | |
| 1362 | if (check_skip) { |
| 1363 | if (path->slots[i] == 0) { |
| 1364 | skip_level = i + 1; |
| 1365 | continue; |
| 1366 | } |
| 1367 | |
| 1368 | if (path->keep_locks) { |
| 1369 | u32 nritems; |
| 1370 | |
| 1371 | nritems = btrfs_header_nritems(path->nodes[i]); |
| 1372 | if (nritems < 1 || path->slots[i] >= nritems - 1) { |
| 1373 | skip_level = i + 1; |
| 1374 | continue; |
| 1375 | } |
| 1376 | } |
| 1377 | } |
| 1378 | |
| 1379 | if (i >= lowest_unlock && i > skip_level) { |
| 1380 | check_skip = false; |
| 1381 | btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]); |
| 1382 | path->locks[i] = 0; |
| 1383 | if (write_lock_level && |
| 1384 | i > min_write_lock_level && |
| 1385 | i <= *write_lock_level) { |
| 1386 | *write_lock_level = i - 1; |
| 1387 | } |
| 1388 | } |
| 1389 | } |
| 1390 | } |
| 1391 | |
| 1392 | /* |
| 1393 | * helper function for btrfs_search_slot. The goal is to find a block |
| 1394 | * in cache without setting the path to blocking. If we find the block |
| 1395 | * we return zero and the path is unchanged. |
| 1396 | * |
| 1397 | * If we can't find the block, we set the path blocking and do some |
| 1398 | * reada. -EAGAIN is returned and the search must be repeated. |
| 1399 | */ |
| 1400 | static int |
| 1401 | read_block_for_search(struct btrfs_root *root, struct btrfs_path *p, |
| 1402 | struct extent_buffer **eb_ret, int level, int slot, |
| 1403 | const struct btrfs_key *key) |
| 1404 | { |
| 1405 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 1406 | u64 blocknr; |
| 1407 | u64 gen; |
| 1408 | struct extent_buffer *tmp; |
| 1409 | struct btrfs_key first_key; |
| 1410 | int ret; |
| 1411 | int parent_level; |
| 1412 | |
| 1413 | blocknr = btrfs_node_blockptr(*eb_ret, slot); |
| 1414 | gen = btrfs_node_ptr_generation(*eb_ret, slot); |
| 1415 | parent_level = btrfs_header_level(*eb_ret); |
| 1416 | btrfs_node_key_to_cpu(*eb_ret, &first_key, slot); |
| 1417 | |
| 1418 | tmp = find_extent_buffer(fs_info, blocknr); |
| 1419 | if (tmp) { |
| 1420 | if (p->reada == READA_FORWARD_ALWAYS) |
| 1421 | reada_for_search(fs_info, p, level, slot, key->objectid); |
| 1422 | |
| 1423 | /* first we do an atomic uptodate check */ |
| 1424 | if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) { |
| 1425 | /* |
| 1426 | * Do extra check for first_key, eb can be stale due to |
| 1427 | * being cached, read from scrub, or have multiple |
| 1428 | * parents (shared tree blocks). |
| 1429 | */ |
| 1430 | if (btrfs_verify_level_key(tmp, |
| 1431 | parent_level - 1, &first_key, gen)) { |
| 1432 | free_extent_buffer(tmp); |
| 1433 | return -EUCLEAN; |
| 1434 | } |
| 1435 | *eb_ret = tmp; |
| 1436 | return 0; |
| 1437 | } |
| 1438 | |
| 1439 | /* now we're allowed to do a blocking uptodate check */ |
| 1440 | ret = btrfs_read_buffer(tmp, gen, parent_level - 1, &first_key); |
| 1441 | if (ret) { |
| 1442 | free_extent_buffer(tmp); |
| 1443 | btrfs_release_path(p); |
| 1444 | return -EIO; |
| 1445 | } |
| 1446 | *eb_ret = tmp; |
| 1447 | return 0; |
| 1448 | } |
| 1449 | |
| 1450 | /* |
| 1451 | * reduce lock contention at high levels |
| 1452 | * of the btree by dropping locks before |
| 1453 | * we read. Don't release the lock on the current |
| 1454 | * level because we need to walk this node to figure |
| 1455 | * out which blocks to read. |
| 1456 | */ |
| 1457 | btrfs_unlock_up_safe(p, level + 1); |
| 1458 | |
| 1459 | if (p->reada != READA_NONE) |
| 1460 | reada_for_search(fs_info, p, level, slot, key->objectid); |
| 1461 | |
| 1462 | ret = -EAGAIN; |
| 1463 | tmp = read_tree_block(fs_info, blocknr, root->root_key.objectid, |
| 1464 | gen, parent_level - 1, &first_key); |
| 1465 | if (IS_ERR(tmp)) { |
| 1466 | btrfs_release_path(p); |
| 1467 | return PTR_ERR(tmp); |
| 1468 | } |
| 1469 | /* |
| 1470 | * If the read above didn't mark this buffer up to date, |
| 1471 | * it will never end up being up to date. Set ret to EIO now |
| 1472 | * and give up so that our caller doesn't loop forever |
| 1473 | * on our EAGAINs. |
| 1474 | */ |
| 1475 | if (!extent_buffer_uptodate(tmp)) |
| 1476 | ret = -EIO; |
| 1477 | free_extent_buffer(tmp); |
| 1478 | |
| 1479 | btrfs_release_path(p); |
| 1480 | return ret; |
| 1481 | } |
| 1482 | |
| 1483 | /* |
| 1484 | * helper function for btrfs_search_slot. This does all of the checks |
| 1485 | * for node-level blocks and does any balancing required based on |
| 1486 | * the ins_len. |
| 1487 | * |
| 1488 | * If no extra work was required, zero is returned. If we had to |
| 1489 | * drop the path, -EAGAIN is returned and btrfs_search_slot must |
| 1490 | * start over |
| 1491 | */ |
| 1492 | static int |
| 1493 | setup_nodes_for_search(struct btrfs_trans_handle *trans, |
| 1494 | struct btrfs_root *root, struct btrfs_path *p, |
| 1495 | struct extent_buffer *b, int level, int ins_len, |
| 1496 | int *write_lock_level) |
| 1497 | { |
| 1498 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 1499 | int ret = 0; |
| 1500 | |
| 1501 | if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= |
| 1502 | BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) { |
| 1503 | |
| 1504 | if (*write_lock_level < level + 1) { |
| 1505 | *write_lock_level = level + 1; |
| 1506 | btrfs_release_path(p); |
| 1507 | return -EAGAIN; |
| 1508 | } |
| 1509 | |
| 1510 | reada_for_balance(p, level); |
| 1511 | ret = split_node(trans, root, p, level); |
| 1512 | |
| 1513 | b = p->nodes[level]; |
| 1514 | } else if (ins_len < 0 && btrfs_header_nritems(b) < |
| 1515 | BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 2) { |
| 1516 | |
| 1517 | if (*write_lock_level < level + 1) { |
| 1518 | *write_lock_level = level + 1; |
| 1519 | btrfs_release_path(p); |
| 1520 | return -EAGAIN; |
| 1521 | } |
| 1522 | |
| 1523 | reada_for_balance(p, level); |
| 1524 | ret = balance_level(trans, root, p, level); |
| 1525 | if (ret) |
| 1526 | return ret; |
| 1527 | |
| 1528 | b = p->nodes[level]; |
| 1529 | if (!b) { |
| 1530 | btrfs_release_path(p); |
| 1531 | return -EAGAIN; |
| 1532 | } |
| 1533 | BUG_ON(btrfs_header_nritems(b) == 1); |
| 1534 | } |
| 1535 | return ret; |
| 1536 | } |
| 1537 | |
| 1538 | int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path, |
| 1539 | u64 iobjectid, u64 ioff, u8 key_type, |
| 1540 | struct btrfs_key *found_key) |
| 1541 | { |
| 1542 | int ret; |
| 1543 | struct btrfs_key key; |
| 1544 | struct extent_buffer *eb; |
| 1545 | |
| 1546 | ASSERT(path); |
| 1547 | ASSERT(found_key); |
| 1548 | |
| 1549 | key.type = key_type; |
| 1550 | key.objectid = iobjectid; |
| 1551 | key.offset = ioff; |
| 1552 | |
| 1553 | ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); |
| 1554 | if (ret < 0) |
| 1555 | return ret; |
| 1556 | |
| 1557 | eb = path->nodes[0]; |
| 1558 | if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { |
| 1559 | ret = btrfs_next_leaf(fs_root, path); |
| 1560 | if (ret) |
| 1561 | return ret; |
| 1562 | eb = path->nodes[0]; |
| 1563 | } |
| 1564 | |
| 1565 | btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); |
| 1566 | if (found_key->type != key.type || |
| 1567 | found_key->objectid != key.objectid) |
| 1568 | return 1; |
| 1569 | |
| 1570 | return 0; |
| 1571 | } |
| 1572 | |
| 1573 | static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, |
| 1574 | struct btrfs_path *p, |
| 1575 | int write_lock_level) |
| 1576 | { |
| 1577 | struct extent_buffer *b; |
| 1578 | int root_lock = 0; |
| 1579 | int level = 0; |
| 1580 | |
| 1581 | if (p->search_commit_root) { |
| 1582 | b = root->commit_root; |
| 1583 | atomic_inc(&b->refs); |
| 1584 | level = btrfs_header_level(b); |
| 1585 | /* |
| 1586 | * Ensure that all callers have set skip_locking when |
| 1587 | * p->search_commit_root = 1. |
| 1588 | */ |
| 1589 | ASSERT(p->skip_locking == 1); |
| 1590 | |
| 1591 | goto out; |
| 1592 | } |
| 1593 | |
| 1594 | if (p->skip_locking) { |
| 1595 | b = btrfs_root_node(root); |
| 1596 | level = btrfs_header_level(b); |
| 1597 | goto out; |
| 1598 | } |
| 1599 | |
| 1600 | /* We try very hard to do read locks on the root */ |
| 1601 | root_lock = BTRFS_READ_LOCK; |
| 1602 | |
| 1603 | /* |
| 1604 | * If the level is set to maximum, we can skip trying to get the read |
| 1605 | * lock. |
| 1606 | */ |
| 1607 | if (write_lock_level < BTRFS_MAX_LEVEL) { |
| 1608 | /* |
| 1609 | * We don't know the level of the root node until we actually |
| 1610 | * have it read locked |
| 1611 | */ |
| 1612 | b = btrfs_read_lock_root_node(root); |
| 1613 | level = btrfs_header_level(b); |
| 1614 | if (level > write_lock_level) |
| 1615 | goto out; |
| 1616 | |
| 1617 | /* Whoops, must trade for write lock */ |
| 1618 | btrfs_tree_read_unlock(b); |
| 1619 | free_extent_buffer(b); |
| 1620 | } |
| 1621 | |
| 1622 | b = btrfs_lock_root_node(root); |
| 1623 | root_lock = BTRFS_WRITE_LOCK; |
| 1624 | |
| 1625 | /* The level might have changed, check again */ |
| 1626 | level = btrfs_header_level(b); |
| 1627 | |
| 1628 | out: |
| 1629 | /* |
| 1630 | * The root may have failed to write out at some point, and thus is no |
| 1631 | * longer valid, return an error in this case. |
| 1632 | */ |
| 1633 | if (!extent_buffer_uptodate(b)) { |
| 1634 | if (root_lock) |
| 1635 | btrfs_tree_unlock_rw(b, root_lock); |
| 1636 | free_extent_buffer(b); |
| 1637 | return ERR_PTR(-EIO); |
| 1638 | } |
| 1639 | |
| 1640 | p->nodes[level] = b; |
| 1641 | if (!p->skip_locking) |
| 1642 | p->locks[level] = root_lock; |
| 1643 | /* |
| 1644 | * Callers are responsible for dropping b's references. |
| 1645 | */ |
| 1646 | return b; |
| 1647 | } |
| 1648 | |
| 1649 | /* |
| 1650 | * Replace the extent buffer at the lowest level of the path with a cloned |
| 1651 | * version. The purpose is to be able to use it safely, after releasing the |
| 1652 | * commit root semaphore, even if relocation is happening in parallel, the |
| 1653 | * transaction used for relocation is committed and the extent buffer is |
| 1654 | * reallocated in the next transaction. |
| 1655 | * |
| 1656 | * This is used in a context where the caller does not prevent transaction |
| 1657 | * commits from happening, either by holding a transaction handle or holding |
| 1658 | * some lock, while it's doing searches through a commit root. |
| 1659 | * At the moment it's only used for send operations. |
| 1660 | */ |
| 1661 | static int finish_need_commit_sem_search(struct btrfs_path *path) |
| 1662 | { |
| 1663 | const int i = path->lowest_level; |
| 1664 | const int slot = path->slots[i]; |
| 1665 | struct extent_buffer *lowest = path->nodes[i]; |
| 1666 | struct extent_buffer *clone; |
| 1667 | |
| 1668 | ASSERT(path->need_commit_sem); |
| 1669 | |
| 1670 | if (!lowest) |
| 1671 | return 0; |
| 1672 | |
| 1673 | lockdep_assert_held_read(&lowest->fs_info->commit_root_sem); |
| 1674 | |
| 1675 | clone = btrfs_clone_extent_buffer(lowest); |
| 1676 | if (!clone) |
| 1677 | return -ENOMEM; |
| 1678 | |
| 1679 | btrfs_release_path(path); |
| 1680 | path->nodes[i] = clone; |
| 1681 | path->slots[i] = slot; |
| 1682 | |
| 1683 | return 0; |
| 1684 | } |
| 1685 | |
| 1686 | static inline int search_for_key_slot(struct extent_buffer *eb, |
| 1687 | int search_low_slot, |
| 1688 | const struct btrfs_key *key, |
| 1689 | int prev_cmp, |
| 1690 | int *slot) |
| 1691 | { |
| 1692 | /* |
| 1693 | * If a previous call to btrfs_bin_search() on a parent node returned an |
| 1694 | * exact match (prev_cmp == 0), we can safely assume the target key will |
| 1695 | * always be at slot 0 on lower levels, since each key pointer |
| 1696 | * (struct btrfs_key_ptr) refers to the lowest key accessible from the |
| 1697 | * subtree it points to. Thus we can skip searching lower levels. |
| 1698 | */ |
| 1699 | if (prev_cmp == 0) { |
| 1700 | *slot = 0; |
| 1701 | return 0; |
| 1702 | } |
| 1703 | |
| 1704 | return generic_bin_search(eb, search_low_slot, key, slot); |
| 1705 | } |
| 1706 | |
| 1707 | static int search_leaf(struct btrfs_trans_handle *trans, |
| 1708 | struct btrfs_root *root, |
| 1709 | const struct btrfs_key *key, |
| 1710 | struct btrfs_path *path, |
| 1711 | int ins_len, |
| 1712 | int prev_cmp) |
| 1713 | { |
| 1714 | struct extent_buffer *leaf = path->nodes[0]; |
| 1715 | int leaf_free_space = -1; |
| 1716 | int search_low_slot = 0; |
| 1717 | int ret; |
| 1718 | bool do_bin_search = true; |
| 1719 | |
| 1720 | /* |
| 1721 | * If we are doing an insertion, the leaf has enough free space and the |
| 1722 | * destination slot for the key is not slot 0, then we can unlock our |
| 1723 | * write lock on the parent, and any other upper nodes, before doing the |
| 1724 | * binary search on the leaf (with search_for_key_slot()), allowing other |
| 1725 | * tasks to lock the parent and any other upper nodes. |
| 1726 | */ |
| 1727 | if (ins_len > 0) { |
| 1728 | /* |
| 1729 | * Cache the leaf free space, since we will need it later and it |
| 1730 | * will not change until then. |
| 1731 | */ |
| 1732 | leaf_free_space = btrfs_leaf_free_space(leaf); |
| 1733 | |
| 1734 | /* |
| 1735 | * !path->locks[1] means we have a single node tree, the leaf is |
| 1736 | * the root of the tree. |
| 1737 | */ |
| 1738 | if (path->locks[1] && leaf_free_space >= ins_len) { |
| 1739 | struct btrfs_disk_key first_key; |
| 1740 | |
| 1741 | ASSERT(btrfs_header_nritems(leaf) > 0); |
| 1742 | btrfs_item_key(leaf, &first_key, 0); |
| 1743 | |
| 1744 | /* |
| 1745 | * Doing the extra comparison with the first key is cheap, |
| 1746 | * taking into account that the first key is very likely |
| 1747 | * already in a cache line because it immediately follows |
| 1748 | * the extent buffer's header and we have recently accessed |
| 1749 | * the header's level field. |
| 1750 | */ |
| 1751 | ret = comp_keys(&first_key, key); |
| 1752 | if (ret < 0) { |
| 1753 | /* |
| 1754 | * The first key is smaller than the key we want |
| 1755 | * to insert, so we are safe to unlock all upper |
| 1756 | * nodes and we have to do the binary search. |
| 1757 | * |
| 1758 | * We do use btrfs_unlock_up_safe() and not |
| 1759 | * unlock_up() because the later does not unlock |
| 1760 | * nodes with a slot of 0 - we can safely unlock |
| 1761 | * any node even if its slot is 0 since in this |
| 1762 | * case the key does not end up at slot 0 of the |
| 1763 | * leaf and there's no need to split the leaf. |
| 1764 | */ |
| 1765 | btrfs_unlock_up_safe(path, 1); |
| 1766 | search_low_slot = 1; |
| 1767 | } else { |
| 1768 | /* |
| 1769 | * The first key is >= then the key we want to |
| 1770 | * insert, so we can skip the binary search as |
| 1771 | * the target key will be at slot 0. |
| 1772 | * |
| 1773 | * We can not unlock upper nodes when the key is |
| 1774 | * less than the first key, because we will need |
| 1775 | * to update the key at slot 0 of the parent node |
| 1776 | * and possibly of other upper nodes too. |
| 1777 | * If the key matches the first key, then we can |
| 1778 | * unlock all the upper nodes, using |
| 1779 | * btrfs_unlock_up_safe() instead of unlock_up() |
| 1780 | * as stated above. |
| 1781 | */ |
| 1782 | if (ret == 0) |
| 1783 | btrfs_unlock_up_safe(path, 1); |
| 1784 | /* |
| 1785 | * ret is already 0 or 1, matching the result of |
| 1786 | * a btrfs_bin_search() call, so there is no need |
| 1787 | * to adjust it. |
| 1788 | */ |
| 1789 | do_bin_search = false; |
| 1790 | path->slots[0] = 0; |
| 1791 | } |
| 1792 | } |
| 1793 | } |
| 1794 | |
| 1795 | if (do_bin_search) { |
| 1796 | ret = search_for_key_slot(leaf, search_low_slot, key, |
| 1797 | prev_cmp, &path->slots[0]); |
| 1798 | if (ret < 0) |
| 1799 | return ret; |
| 1800 | } |
| 1801 | |
| 1802 | if (ins_len > 0) { |
| 1803 | /* |
| 1804 | * Item key already exists. In this case, if we are allowed to |
| 1805 | * insert the item (for example, in dir_item case, item key |
| 1806 | * collision is allowed), it will be merged with the original |
| 1807 | * item. Only the item size grows, no new btrfs item will be |
| 1808 | * added. If search_for_extension is not set, ins_len already |
| 1809 | * accounts the size btrfs_item, deduct it here so leaf space |
| 1810 | * check will be correct. |
| 1811 | */ |
| 1812 | if (ret == 0 && !path->search_for_extension) { |
| 1813 | ASSERT(ins_len >= sizeof(struct btrfs_item)); |
| 1814 | ins_len -= sizeof(struct btrfs_item); |
| 1815 | } |
| 1816 | |
| 1817 | ASSERT(leaf_free_space >= 0); |
| 1818 | |
| 1819 | if (leaf_free_space < ins_len) { |
| 1820 | int err; |
| 1821 | |
| 1822 | err = split_leaf(trans, root, key, path, ins_len, |
| 1823 | (ret == 0)); |
| 1824 | ASSERT(err <= 0); |
| 1825 | if (WARN_ON(err > 0)) |
| 1826 | err = -EUCLEAN; |
| 1827 | if (err) |
| 1828 | ret = err; |
| 1829 | } |
| 1830 | } |
| 1831 | |
| 1832 | return ret; |
| 1833 | } |
| 1834 | |
| 1835 | /* |
| 1836 | * btrfs_search_slot - look for a key in a tree and perform necessary |
| 1837 | * modifications to preserve tree invariants. |
| 1838 | * |
| 1839 | * @trans: Handle of transaction, used when modifying the tree |
| 1840 | * @p: Holds all btree nodes along the search path |
| 1841 | * @root: The root node of the tree |
| 1842 | * @key: The key we are looking for |
| 1843 | * @ins_len: Indicates purpose of search: |
| 1844 | * >0 for inserts it's size of item inserted (*) |
| 1845 | * <0 for deletions |
| 1846 | * 0 for plain searches, not modifying the tree |
| 1847 | * |
| 1848 | * (*) If size of item inserted doesn't include |
| 1849 | * sizeof(struct btrfs_item), then p->search_for_extension must |
| 1850 | * be set. |
| 1851 | * @cow: boolean should CoW operations be performed. Must always be 1 |
| 1852 | * when modifying the tree. |
| 1853 | * |
| 1854 | * If @ins_len > 0, nodes and leaves will be split as we walk down the tree. |
| 1855 | * If @ins_len < 0, nodes will be merged as we walk down the tree (if possible) |
| 1856 | * |
| 1857 | * If @key is found, 0 is returned and you can find the item in the leaf level |
| 1858 | * of the path (level 0) |
| 1859 | * |
| 1860 | * If @key isn't found, 1 is returned and the leaf level of the path (level 0) |
| 1861 | * points to the slot where it should be inserted |
| 1862 | * |
| 1863 | * If an error is encountered while searching the tree a negative error number |
| 1864 | * is returned |
| 1865 | */ |
| 1866 | int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 1867 | const struct btrfs_key *key, struct btrfs_path *p, |
| 1868 | int ins_len, int cow) |
| 1869 | { |
| 1870 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 1871 | struct extent_buffer *b; |
| 1872 | int slot; |
| 1873 | int ret; |
| 1874 | int err; |
| 1875 | int level; |
| 1876 | int lowest_unlock = 1; |
| 1877 | /* everything at write_lock_level or lower must be write locked */ |
| 1878 | int write_lock_level = 0; |
| 1879 | u8 lowest_level = 0; |
| 1880 | int min_write_lock_level; |
| 1881 | int prev_cmp; |
| 1882 | |
| 1883 | lowest_level = p->lowest_level; |
| 1884 | WARN_ON(lowest_level && ins_len > 0); |
| 1885 | WARN_ON(p->nodes[0] != NULL); |
| 1886 | BUG_ON(!cow && ins_len); |
| 1887 | |
| 1888 | if (ins_len < 0) { |
| 1889 | lowest_unlock = 2; |
| 1890 | |
| 1891 | /* when we are removing items, we might have to go up to level |
| 1892 | * two as we update tree pointers Make sure we keep write |
| 1893 | * for those levels as well |
| 1894 | */ |
| 1895 | write_lock_level = 2; |
| 1896 | } else if (ins_len > 0) { |
| 1897 | /* |
| 1898 | * for inserting items, make sure we have a write lock on |
| 1899 | * level 1 so we can update keys |
| 1900 | */ |
| 1901 | write_lock_level = 1; |
| 1902 | } |
| 1903 | |
| 1904 | if (!cow) |
| 1905 | write_lock_level = -1; |
| 1906 | |
| 1907 | if (cow && (p->keep_locks || p->lowest_level)) |
| 1908 | write_lock_level = BTRFS_MAX_LEVEL; |
| 1909 | |
| 1910 | min_write_lock_level = write_lock_level; |
| 1911 | |
| 1912 | if (p->need_commit_sem) { |
| 1913 | ASSERT(p->search_commit_root); |
| 1914 | down_read(&fs_info->commit_root_sem); |
| 1915 | } |
| 1916 | |
| 1917 | again: |
| 1918 | prev_cmp = -1; |
| 1919 | b = btrfs_search_slot_get_root(root, p, write_lock_level); |
| 1920 | if (IS_ERR(b)) { |
| 1921 | ret = PTR_ERR(b); |
| 1922 | goto done; |
| 1923 | } |
| 1924 | |
| 1925 | while (b) { |
| 1926 | int dec = 0; |
| 1927 | |
| 1928 | level = btrfs_header_level(b); |
| 1929 | |
| 1930 | if (cow) { |
| 1931 | bool last_level = (level == (BTRFS_MAX_LEVEL - 1)); |
| 1932 | |
| 1933 | /* |
| 1934 | * if we don't really need to cow this block |
| 1935 | * then we don't want to set the path blocking, |
| 1936 | * so we test it here |
| 1937 | */ |
| 1938 | if (!should_cow_block(trans, root, b)) |
| 1939 | goto cow_done; |
| 1940 | |
| 1941 | /* |
| 1942 | * must have write locks on this node and the |
| 1943 | * parent |
| 1944 | */ |
| 1945 | if (level > write_lock_level || |
| 1946 | (level + 1 > write_lock_level && |
| 1947 | level + 1 < BTRFS_MAX_LEVEL && |
| 1948 | p->nodes[level + 1])) { |
| 1949 | write_lock_level = level + 1; |
| 1950 | btrfs_release_path(p); |
| 1951 | goto again; |
| 1952 | } |
| 1953 | |
| 1954 | if (last_level) |
| 1955 | err = btrfs_cow_block(trans, root, b, NULL, 0, |
| 1956 | &b, |
| 1957 | BTRFS_NESTING_COW); |
| 1958 | else |
| 1959 | err = btrfs_cow_block(trans, root, b, |
| 1960 | p->nodes[level + 1], |
| 1961 | p->slots[level + 1], &b, |
| 1962 | BTRFS_NESTING_COW); |
| 1963 | if (err) { |
| 1964 | ret = err; |
| 1965 | goto done; |
| 1966 | } |
| 1967 | } |
| 1968 | cow_done: |
| 1969 | p->nodes[level] = b; |
| 1970 | |
| 1971 | /* |
| 1972 | * we have a lock on b and as long as we aren't changing |
| 1973 | * the tree, there is no way to for the items in b to change. |
| 1974 | * It is safe to drop the lock on our parent before we |
| 1975 | * go through the expensive btree search on b. |
| 1976 | * |
| 1977 | * If we're inserting or deleting (ins_len != 0), then we might |
| 1978 | * be changing slot zero, which may require changing the parent. |
| 1979 | * So, we can't drop the lock until after we know which slot |
| 1980 | * we're operating on. |
| 1981 | */ |
| 1982 | if (!ins_len && !p->keep_locks) { |
| 1983 | int u = level + 1; |
| 1984 | |
| 1985 | if (u < BTRFS_MAX_LEVEL && p->locks[u]) { |
| 1986 | btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]); |
| 1987 | p->locks[u] = 0; |
| 1988 | } |
| 1989 | } |
| 1990 | |
| 1991 | if (level == 0) { |
| 1992 | if (ins_len > 0) |
| 1993 | ASSERT(write_lock_level >= 1); |
| 1994 | |
| 1995 | ret = search_leaf(trans, root, key, p, ins_len, prev_cmp); |
| 1996 | if (!p->search_for_split) |
| 1997 | unlock_up(p, level, lowest_unlock, |
| 1998 | min_write_lock_level, NULL); |
| 1999 | goto done; |
| 2000 | } |
| 2001 | |
| 2002 | ret = search_for_key_slot(b, 0, key, prev_cmp, &slot); |
| 2003 | if (ret < 0) |
| 2004 | goto done; |
| 2005 | prev_cmp = ret; |
| 2006 | |
| 2007 | if (ret && slot > 0) { |
| 2008 | dec = 1; |
| 2009 | slot--; |
| 2010 | } |
| 2011 | p->slots[level] = slot; |
| 2012 | err = setup_nodes_for_search(trans, root, p, b, level, ins_len, |
| 2013 | &write_lock_level); |
| 2014 | if (err == -EAGAIN) |
| 2015 | goto again; |
| 2016 | if (err) { |
| 2017 | ret = err; |
| 2018 | goto done; |
| 2019 | } |
| 2020 | b = p->nodes[level]; |
| 2021 | slot = p->slots[level]; |
| 2022 | |
| 2023 | /* |
| 2024 | * Slot 0 is special, if we change the key we have to update |
| 2025 | * the parent pointer which means we must have a write lock on |
| 2026 | * the parent |
| 2027 | */ |
| 2028 | if (slot == 0 && ins_len && write_lock_level < level + 1) { |
| 2029 | write_lock_level = level + 1; |
| 2030 | btrfs_release_path(p); |
| 2031 | goto again; |
| 2032 | } |
| 2033 | |
| 2034 | unlock_up(p, level, lowest_unlock, min_write_lock_level, |
| 2035 | &write_lock_level); |
| 2036 | |
| 2037 | if (level == lowest_level) { |
| 2038 | if (dec) |
| 2039 | p->slots[level]++; |
| 2040 | goto done; |
| 2041 | } |
| 2042 | |
| 2043 | err = read_block_for_search(root, p, &b, level, slot, key); |
| 2044 | if (err == -EAGAIN) |
| 2045 | goto again; |
| 2046 | if (err) { |
| 2047 | ret = err; |
| 2048 | goto done; |
| 2049 | } |
| 2050 | |
| 2051 | if (!p->skip_locking) { |
| 2052 | level = btrfs_header_level(b); |
| 2053 | if (level <= write_lock_level) { |
| 2054 | btrfs_tree_lock(b); |
| 2055 | p->locks[level] = BTRFS_WRITE_LOCK; |
| 2056 | } else { |
| 2057 | btrfs_tree_read_lock(b); |
| 2058 | p->locks[level] = BTRFS_READ_LOCK; |
| 2059 | } |
| 2060 | p->nodes[level] = b; |
| 2061 | } |
| 2062 | } |
| 2063 | ret = 1; |
| 2064 | done: |
| 2065 | if (ret < 0 && !p->skip_release_on_error) |
| 2066 | btrfs_release_path(p); |
| 2067 | |
| 2068 | if (p->need_commit_sem) { |
| 2069 | int ret2; |
| 2070 | |
| 2071 | ret2 = finish_need_commit_sem_search(p); |
| 2072 | up_read(&fs_info->commit_root_sem); |
| 2073 | if (ret2) |
| 2074 | ret = ret2; |
| 2075 | } |
| 2076 | |
| 2077 | return ret; |
| 2078 | } |
| 2079 | ALLOW_ERROR_INJECTION(btrfs_search_slot, ERRNO); |
| 2080 | |
| 2081 | /* |
| 2082 | * Like btrfs_search_slot, this looks for a key in the given tree. It uses the |
| 2083 | * current state of the tree together with the operations recorded in the tree |
| 2084 | * modification log to search for the key in a previous version of this tree, as |
| 2085 | * denoted by the time_seq parameter. |
| 2086 | * |
| 2087 | * Naturally, there is no support for insert, delete or cow operations. |
| 2088 | * |
| 2089 | * The resulting path and return value will be set up as if we called |
| 2090 | * btrfs_search_slot at that point in time with ins_len and cow both set to 0. |
| 2091 | */ |
| 2092 | int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key, |
| 2093 | struct btrfs_path *p, u64 time_seq) |
| 2094 | { |
| 2095 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 2096 | struct extent_buffer *b; |
| 2097 | int slot; |
| 2098 | int ret; |
| 2099 | int err; |
| 2100 | int level; |
| 2101 | int lowest_unlock = 1; |
| 2102 | u8 lowest_level = 0; |
| 2103 | |
| 2104 | lowest_level = p->lowest_level; |
| 2105 | WARN_ON(p->nodes[0] != NULL); |
| 2106 | |
| 2107 | if (p->search_commit_root) { |
| 2108 | BUG_ON(time_seq); |
| 2109 | return btrfs_search_slot(NULL, root, key, p, 0, 0); |
| 2110 | } |
| 2111 | |
| 2112 | again: |
| 2113 | b = btrfs_get_old_root(root, time_seq); |
| 2114 | if (!b) { |
| 2115 | ret = -EIO; |
| 2116 | goto done; |
| 2117 | } |
| 2118 | level = btrfs_header_level(b); |
| 2119 | p->locks[level] = BTRFS_READ_LOCK; |
| 2120 | |
| 2121 | while (b) { |
| 2122 | int dec = 0; |
| 2123 | |
| 2124 | level = btrfs_header_level(b); |
| 2125 | p->nodes[level] = b; |
| 2126 | |
| 2127 | /* |
| 2128 | * we have a lock on b and as long as we aren't changing |
| 2129 | * the tree, there is no way to for the items in b to change. |
| 2130 | * It is safe to drop the lock on our parent before we |
| 2131 | * go through the expensive btree search on b. |
| 2132 | */ |
| 2133 | btrfs_unlock_up_safe(p, level + 1); |
| 2134 | |
| 2135 | ret = btrfs_bin_search(b, key, &slot); |
| 2136 | if (ret < 0) |
| 2137 | goto done; |
| 2138 | |
| 2139 | if (level == 0) { |
| 2140 | p->slots[level] = slot; |
| 2141 | unlock_up(p, level, lowest_unlock, 0, NULL); |
| 2142 | goto done; |
| 2143 | } |
| 2144 | |
| 2145 | if (ret && slot > 0) { |
| 2146 | dec = 1; |
| 2147 | slot--; |
| 2148 | } |
| 2149 | p->slots[level] = slot; |
| 2150 | unlock_up(p, level, lowest_unlock, 0, NULL); |
| 2151 | |
| 2152 | if (level == lowest_level) { |
| 2153 | if (dec) |
| 2154 | p->slots[level]++; |
| 2155 | goto done; |
| 2156 | } |
| 2157 | |
| 2158 | err = read_block_for_search(root, p, &b, level, slot, key); |
| 2159 | if (err == -EAGAIN) |
| 2160 | goto again; |
| 2161 | if (err) { |
| 2162 | ret = err; |
| 2163 | goto done; |
| 2164 | } |
| 2165 | |
| 2166 | level = btrfs_header_level(b); |
| 2167 | btrfs_tree_read_lock(b); |
| 2168 | b = btrfs_tree_mod_log_rewind(fs_info, p, b, time_seq); |
| 2169 | if (!b) { |
| 2170 | ret = -ENOMEM; |
| 2171 | goto done; |
| 2172 | } |
| 2173 | p->locks[level] = BTRFS_READ_LOCK; |
| 2174 | p->nodes[level] = b; |
| 2175 | } |
| 2176 | ret = 1; |
| 2177 | done: |
| 2178 | if (ret < 0) |
| 2179 | btrfs_release_path(p); |
| 2180 | |
| 2181 | return ret; |
| 2182 | } |
| 2183 | |
| 2184 | /* |
| 2185 | * helper to use instead of search slot if no exact match is needed but |
| 2186 | * instead the next or previous item should be returned. |
| 2187 | * When find_higher is true, the next higher item is returned, the next lower |
| 2188 | * otherwise. |
| 2189 | * When return_any and find_higher are both true, and no higher item is found, |
| 2190 | * return the next lower instead. |
| 2191 | * When return_any is true and find_higher is false, and no lower item is found, |
| 2192 | * return the next higher instead. |
| 2193 | * It returns 0 if any item is found, 1 if none is found (tree empty), and |
| 2194 | * < 0 on error |
| 2195 | */ |
| 2196 | int btrfs_search_slot_for_read(struct btrfs_root *root, |
| 2197 | const struct btrfs_key *key, |
| 2198 | struct btrfs_path *p, int find_higher, |
| 2199 | int return_any) |
| 2200 | { |
| 2201 | int ret; |
| 2202 | struct extent_buffer *leaf; |
| 2203 | |
| 2204 | again: |
| 2205 | ret = btrfs_search_slot(NULL, root, key, p, 0, 0); |
| 2206 | if (ret <= 0) |
| 2207 | return ret; |
| 2208 | /* |
| 2209 | * a return value of 1 means the path is at the position where the |
| 2210 | * item should be inserted. Normally this is the next bigger item, |
| 2211 | * but in case the previous item is the last in a leaf, path points |
| 2212 | * to the first free slot in the previous leaf, i.e. at an invalid |
| 2213 | * item. |
| 2214 | */ |
| 2215 | leaf = p->nodes[0]; |
| 2216 | |
| 2217 | if (find_higher) { |
| 2218 | if (p->slots[0] >= btrfs_header_nritems(leaf)) { |
| 2219 | ret = btrfs_next_leaf(root, p); |
| 2220 | if (ret <= 0) |
| 2221 | return ret; |
| 2222 | if (!return_any) |
| 2223 | return 1; |
| 2224 | /* |
| 2225 | * no higher item found, return the next |
| 2226 | * lower instead |
| 2227 | */ |
| 2228 | return_any = 0; |
| 2229 | find_higher = 0; |
| 2230 | btrfs_release_path(p); |
| 2231 | goto again; |
| 2232 | } |
| 2233 | } else { |
| 2234 | if (p->slots[0] == 0) { |
| 2235 | ret = btrfs_prev_leaf(root, p); |
| 2236 | if (ret < 0) |
| 2237 | return ret; |
| 2238 | if (!ret) { |
| 2239 | leaf = p->nodes[0]; |
| 2240 | if (p->slots[0] == btrfs_header_nritems(leaf)) |
| 2241 | p->slots[0]--; |
| 2242 | return 0; |
| 2243 | } |
| 2244 | if (!return_any) |
| 2245 | return 1; |
| 2246 | /* |
| 2247 | * no lower item found, return the next |
| 2248 | * higher instead |
| 2249 | */ |
| 2250 | return_any = 0; |
| 2251 | find_higher = 1; |
| 2252 | btrfs_release_path(p); |
| 2253 | goto again; |
| 2254 | } else { |
| 2255 | --p->slots[0]; |
| 2256 | } |
| 2257 | } |
| 2258 | return 0; |
| 2259 | } |
| 2260 | |
| 2261 | /* |
| 2262 | * Execute search and call btrfs_previous_item to traverse backwards if the item |
| 2263 | * was not found. |
| 2264 | * |
| 2265 | * Return 0 if found, 1 if not found and < 0 if error. |
| 2266 | */ |
| 2267 | int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, |
| 2268 | struct btrfs_path *path) |
| 2269 | { |
| 2270 | int ret; |
| 2271 | |
| 2272 | ret = btrfs_search_slot(NULL, root, key, path, 0, 0); |
| 2273 | if (ret > 0) |
| 2274 | ret = btrfs_previous_item(root, path, key->objectid, key->type); |
| 2275 | |
| 2276 | if (ret == 0) |
| 2277 | btrfs_item_key_to_cpu(path->nodes[0], key, path->slots[0]); |
| 2278 | |
| 2279 | return ret; |
| 2280 | } |
| 2281 | |
| 2282 | /* |
| 2283 | * adjust the pointers going up the tree, starting at level |
| 2284 | * making sure the right key of each node is points to 'key'. |
| 2285 | * This is used after shifting pointers to the left, so it stops |
| 2286 | * fixing up pointers when a given leaf/node is not in slot 0 of the |
| 2287 | * higher levels |
| 2288 | * |
| 2289 | */ |
| 2290 | static void fixup_low_keys(struct btrfs_path *path, |
| 2291 | struct btrfs_disk_key *key, int level) |
| 2292 | { |
| 2293 | int i; |
| 2294 | struct extent_buffer *t; |
| 2295 | int ret; |
| 2296 | |
| 2297 | for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| 2298 | int tslot = path->slots[i]; |
| 2299 | |
| 2300 | if (!path->nodes[i]) |
| 2301 | break; |
| 2302 | t = path->nodes[i]; |
| 2303 | ret = btrfs_tree_mod_log_insert_key(t, tslot, |
| 2304 | BTRFS_MOD_LOG_KEY_REPLACE, GFP_ATOMIC); |
| 2305 | BUG_ON(ret < 0); |
| 2306 | btrfs_set_node_key(t, key, tslot); |
| 2307 | btrfs_mark_buffer_dirty(path->nodes[i]); |
| 2308 | if (tslot != 0) |
| 2309 | break; |
| 2310 | } |
| 2311 | } |
| 2312 | |
| 2313 | /* |
| 2314 | * update item key. |
| 2315 | * |
| 2316 | * This function isn't completely safe. It's the caller's responsibility |
| 2317 | * that the new key won't break the order |
| 2318 | */ |
| 2319 | void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info, |
| 2320 | struct btrfs_path *path, |
| 2321 | const struct btrfs_key *new_key) |
| 2322 | { |
| 2323 | struct btrfs_disk_key disk_key; |
| 2324 | struct extent_buffer *eb; |
| 2325 | int slot; |
| 2326 | |
| 2327 | eb = path->nodes[0]; |
| 2328 | slot = path->slots[0]; |
| 2329 | if (slot > 0) { |
| 2330 | btrfs_item_key(eb, &disk_key, slot - 1); |
| 2331 | if (unlikely(comp_keys(&disk_key, new_key) >= 0)) { |
| 2332 | btrfs_crit(fs_info, |
| 2333 | "slot %u key (%llu %u %llu) new key (%llu %u %llu)", |
| 2334 | slot, btrfs_disk_key_objectid(&disk_key), |
| 2335 | btrfs_disk_key_type(&disk_key), |
| 2336 | btrfs_disk_key_offset(&disk_key), |
| 2337 | new_key->objectid, new_key->type, |
| 2338 | new_key->offset); |
| 2339 | btrfs_print_leaf(eb); |
| 2340 | BUG(); |
| 2341 | } |
| 2342 | } |
| 2343 | if (slot < btrfs_header_nritems(eb) - 1) { |
| 2344 | btrfs_item_key(eb, &disk_key, slot + 1); |
| 2345 | if (unlikely(comp_keys(&disk_key, new_key) <= 0)) { |
| 2346 | btrfs_crit(fs_info, |
| 2347 | "slot %u key (%llu %u %llu) new key (%llu %u %llu)", |
| 2348 | slot, btrfs_disk_key_objectid(&disk_key), |
| 2349 | btrfs_disk_key_type(&disk_key), |
| 2350 | btrfs_disk_key_offset(&disk_key), |
| 2351 | new_key->objectid, new_key->type, |
| 2352 | new_key->offset); |
| 2353 | btrfs_print_leaf(eb); |
| 2354 | BUG(); |
| 2355 | } |
| 2356 | } |
| 2357 | |
| 2358 | btrfs_cpu_key_to_disk(&disk_key, new_key); |
| 2359 | btrfs_set_item_key(eb, &disk_key, slot); |
| 2360 | btrfs_mark_buffer_dirty(eb); |
| 2361 | if (slot == 0) |
| 2362 | fixup_low_keys(path, &disk_key, 1); |
| 2363 | } |
| 2364 | |
| 2365 | /* |
| 2366 | * Check key order of two sibling extent buffers. |
| 2367 | * |
| 2368 | * Return true if something is wrong. |
| 2369 | * Return false if everything is fine. |
| 2370 | * |
| 2371 | * Tree-checker only works inside one tree block, thus the following |
| 2372 | * corruption can not be detected by tree-checker: |
| 2373 | * |
| 2374 | * Leaf @left | Leaf @right |
| 2375 | * -------------------------------------------------------------- |
| 2376 | * | 1 | 2 | 3 | 4 | 5 | f6 | | 7 | 8 | |
| 2377 | * |
| 2378 | * Key f6 in leaf @left itself is valid, but not valid when the next |
| 2379 | * key in leaf @right is 7. |
| 2380 | * This can only be checked at tree block merge time. |
| 2381 | * And since tree checker has ensured all key order in each tree block |
| 2382 | * is correct, we only need to bother the last key of @left and the first |
| 2383 | * key of @right. |
| 2384 | */ |
| 2385 | static bool check_sibling_keys(struct extent_buffer *left, |
| 2386 | struct extent_buffer *right) |
| 2387 | { |
| 2388 | struct btrfs_key left_last; |
| 2389 | struct btrfs_key right_first; |
| 2390 | int level = btrfs_header_level(left); |
| 2391 | int nr_left = btrfs_header_nritems(left); |
| 2392 | int nr_right = btrfs_header_nritems(right); |
| 2393 | |
| 2394 | /* No key to check in one of the tree blocks */ |
| 2395 | if (!nr_left || !nr_right) |
| 2396 | return false; |
| 2397 | |
| 2398 | if (level) { |
| 2399 | btrfs_node_key_to_cpu(left, &left_last, nr_left - 1); |
| 2400 | btrfs_node_key_to_cpu(right, &right_first, 0); |
| 2401 | } else { |
| 2402 | btrfs_item_key_to_cpu(left, &left_last, nr_left - 1); |
| 2403 | btrfs_item_key_to_cpu(right, &right_first, 0); |
| 2404 | } |
| 2405 | |
| 2406 | if (btrfs_comp_cpu_keys(&left_last, &right_first) >= 0) { |
| 2407 | btrfs_crit(left->fs_info, |
| 2408 | "bad key order, sibling blocks, left last (%llu %u %llu) right first (%llu %u %llu)", |
| 2409 | left_last.objectid, left_last.type, |
| 2410 | left_last.offset, right_first.objectid, |
| 2411 | right_first.type, right_first.offset); |
| 2412 | return true; |
| 2413 | } |
| 2414 | return false; |
| 2415 | } |
| 2416 | |
| 2417 | /* |
| 2418 | * try to push data from one node into the next node left in the |
| 2419 | * tree. |
| 2420 | * |
| 2421 | * returns 0 if some ptrs were pushed left, < 0 if there was some horrible |
| 2422 | * error, and > 0 if there was no room in the left hand block. |
| 2423 | */ |
| 2424 | static int push_node_left(struct btrfs_trans_handle *trans, |
| 2425 | struct extent_buffer *dst, |
| 2426 | struct extent_buffer *src, int empty) |
| 2427 | { |
| 2428 | struct btrfs_fs_info *fs_info = trans->fs_info; |
| 2429 | int push_items = 0; |
| 2430 | int src_nritems; |
| 2431 | int dst_nritems; |
| 2432 | int ret = 0; |
| 2433 | |
| 2434 | src_nritems = btrfs_header_nritems(src); |
| 2435 | dst_nritems = btrfs_header_nritems(dst); |
| 2436 | push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems; |
| 2437 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
| 2438 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
| 2439 | |
| 2440 | if (!empty && src_nritems <= 8) |
| 2441 | return 1; |
| 2442 | |
| 2443 | if (push_items <= 0) |
| 2444 | return 1; |
| 2445 | |
| 2446 | if (empty) { |
| 2447 | push_items = min(src_nritems, push_items); |
| 2448 | if (push_items < src_nritems) { |
| 2449 | /* leave at least 8 pointers in the node if |
| 2450 | * we aren't going to empty it |
| 2451 | */ |
| 2452 | if (src_nritems - push_items < 8) { |
| 2453 | if (push_items <= 8) |
| 2454 | return 1; |
| 2455 | push_items -= 8; |
| 2456 | } |
| 2457 | } |
| 2458 | } else |
| 2459 | push_items = min(src_nritems - 8, push_items); |
| 2460 | |
| 2461 | /* dst is the left eb, src is the middle eb */ |
| 2462 | if (check_sibling_keys(dst, src)) { |
| 2463 | ret = -EUCLEAN; |
| 2464 | btrfs_abort_transaction(trans, ret); |
| 2465 | return ret; |
| 2466 | } |
| 2467 | ret = btrfs_tree_mod_log_eb_copy(dst, src, dst_nritems, 0, push_items); |
| 2468 | if (ret) { |
| 2469 | btrfs_abort_transaction(trans, ret); |
| 2470 | return ret; |
| 2471 | } |
| 2472 | copy_extent_buffer(dst, src, |
| 2473 | btrfs_node_key_ptr_offset(dst_nritems), |
| 2474 | btrfs_node_key_ptr_offset(0), |
| 2475 | push_items * sizeof(struct btrfs_key_ptr)); |
| 2476 | |
| 2477 | if (push_items < src_nritems) { |
| 2478 | /* |
| 2479 | * Don't call btrfs_tree_mod_log_insert_move() here, key removal |
| 2480 | * was already fully logged by btrfs_tree_mod_log_eb_copy() above. |
| 2481 | */ |
| 2482 | memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0), |
| 2483 | btrfs_node_key_ptr_offset(push_items), |
| 2484 | (src_nritems - push_items) * |
| 2485 | sizeof(struct btrfs_key_ptr)); |
| 2486 | } |
| 2487 | btrfs_set_header_nritems(src, src_nritems - push_items); |
| 2488 | btrfs_set_header_nritems(dst, dst_nritems + push_items); |
| 2489 | btrfs_mark_buffer_dirty(src); |
| 2490 | btrfs_mark_buffer_dirty(dst); |
| 2491 | |
| 2492 | return ret; |
| 2493 | } |
| 2494 | |
| 2495 | /* |
| 2496 | * try to push data from one node into the next node right in the |
| 2497 | * tree. |
| 2498 | * |
| 2499 | * returns 0 if some ptrs were pushed, < 0 if there was some horrible |
| 2500 | * error, and > 0 if there was no room in the right hand block. |
| 2501 | * |
| 2502 | * this will only push up to 1/2 the contents of the left node over |
| 2503 | */ |
| 2504 | static int balance_node_right(struct btrfs_trans_handle *trans, |
| 2505 | struct extent_buffer *dst, |
| 2506 | struct extent_buffer *src) |
| 2507 | { |
| 2508 | struct btrfs_fs_info *fs_info = trans->fs_info; |
| 2509 | int push_items = 0; |
| 2510 | int max_push; |
| 2511 | int src_nritems; |
| 2512 | int dst_nritems; |
| 2513 | int ret = 0; |
| 2514 | |
| 2515 | WARN_ON(btrfs_header_generation(src) != trans->transid); |
| 2516 | WARN_ON(btrfs_header_generation(dst) != trans->transid); |
| 2517 | |
| 2518 | src_nritems = btrfs_header_nritems(src); |
| 2519 | dst_nritems = btrfs_header_nritems(dst); |
| 2520 | push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems; |
| 2521 | if (push_items <= 0) |
| 2522 | return 1; |
| 2523 | |
| 2524 | if (src_nritems < 4) |
| 2525 | return 1; |
| 2526 | |
| 2527 | max_push = src_nritems / 2 + 1; |
| 2528 | /* don't try to empty the node */ |
| 2529 | if (max_push >= src_nritems) |
| 2530 | return 1; |
| 2531 | |
| 2532 | if (max_push < push_items) |
| 2533 | push_items = max_push; |
| 2534 | |
| 2535 | /* dst is the right eb, src is the middle eb */ |
| 2536 | if (check_sibling_keys(src, dst)) { |
| 2537 | ret = -EUCLEAN; |
| 2538 | btrfs_abort_transaction(trans, ret); |
| 2539 | return ret; |
| 2540 | } |
| 2541 | ret = btrfs_tree_mod_log_insert_move(dst, push_items, 0, dst_nritems); |
| 2542 | BUG_ON(ret < 0); |
| 2543 | memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items), |
| 2544 | btrfs_node_key_ptr_offset(0), |
| 2545 | (dst_nritems) * |
| 2546 | sizeof(struct btrfs_key_ptr)); |
| 2547 | |
| 2548 | ret = btrfs_tree_mod_log_eb_copy(dst, src, 0, src_nritems - push_items, |
| 2549 | push_items); |
| 2550 | if (ret) { |
| 2551 | btrfs_abort_transaction(trans, ret); |
| 2552 | return ret; |
| 2553 | } |
| 2554 | copy_extent_buffer(dst, src, |
| 2555 | btrfs_node_key_ptr_offset(0), |
| 2556 | btrfs_node_key_ptr_offset(src_nritems - push_items), |
| 2557 | push_items * sizeof(struct btrfs_key_ptr)); |
| 2558 | |
| 2559 | btrfs_set_header_nritems(src, src_nritems - push_items); |
| 2560 | btrfs_set_header_nritems(dst, dst_nritems + push_items); |
| 2561 | |
| 2562 | btrfs_mark_buffer_dirty(src); |
| 2563 | btrfs_mark_buffer_dirty(dst); |
| 2564 | |
| 2565 | return ret; |
| 2566 | } |
| 2567 | |
| 2568 | /* |
| 2569 | * helper function to insert a new root level in the tree. |
| 2570 | * A new node is allocated, and a single item is inserted to |
| 2571 | * point to the existing root |
| 2572 | * |
| 2573 | * returns zero on success or < 0 on failure. |
| 2574 | */ |
| 2575 | static noinline int insert_new_root(struct btrfs_trans_handle *trans, |
| 2576 | struct btrfs_root *root, |
| 2577 | struct btrfs_path *path, int level) |
| 2578 | { |
| 2579 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 2580 | u64 lower_gen; |
| 2581 | struct extent_buffer *lower; |
| 2582 | struct extent_buffer *c; |
| 2583 | struct extent_buffer *old; |
| 2584 | struct btrfs_disk_key lower_key; |
| 2585 | int ret; |
| 2586 | |
| 2587 | BUG_ON(path->nodes[level]); |
| 2588 | BUG_ON(path->nodes[level-1] != root->node); |
| 2589 | |
| 2590 | lower = path->nodes[level-1]; |
| 2591 | if (level == 1) |
| 2592 | btrfs_item_key(lower, &lower_key, 0); |
| 2593 | else |
| 2594 | btrfs_node_key(lower, &lower_key, 0); |
| 2595 | |
| 2596 | c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
| 2597 | &lower_key, level, root->node->start, 0, |
| 2598 | BTRFS_NESTING_NEW_ROOT); |
| 2599 | if (IS_ERR(c)) |
| 2600 | return PTR_ERR(c); |
| 2601 | |
| 2602 | root_add_used(root, fs_info->nodesize); |
| 2603 | |
| 2604 | btrfs_set_header_nritems(c, 1); |
| 2605 | btrfs_set_node_key(c, &lower_key, 0); |
| 2606 | btrfs_set_node_blockptr(c, 0, lower->start); |
| 2607 | lower_gen = btrfs_header_generation(lower); |
| 2608 | WARN_ON(lower_gen != trans->transid); |
| 2609 | |
| 2610 | btrfs_set_node_ptr_generation(c, 0, lower_gen); |
| 2611 | |
| 2612 | btrfs_mark_buffer_dirty(c); |
| 2613 | |
| 2614 | old = root->node; |
| 2615 | ret = btrfs_tree_mod_log_insert_root(root->node, c, false); |
| 2616 | BUG_ON(ret < 0); |
| 2617 | rcu_assign_pointer(root->node, c); |
| 2618 | |
| 2619 | /* the super has an extra ref to root->node */ |
| 2620 | free_extent_buffer(old); |
| 2621 | |
| 2622 | add_root_to_dirty_list(root); |
| 2623 | atomic_inc(&c->refs); |
| 2624 | path->nodes[level] = c; |
| 2625 | path->locks[level] = BTRFS_WRITE_LOCK; |
| 2626 | path->slots[level] = 0; |
| 2627 | return 0; |
| 2628 | } |
| 2629 | |
| 2630 | /* |
| 2631 | * worker function to insert a single pointer in a node. |
| 2632 | * the node should have enough room for the pointer already |
| 2633 | * |
| 2634 | * slot and level indicate where you want the key to go, and |
| 2635 | * blocknr is the block the key points to. |
| 2636 | */ |
| 2637 | static void insert_ptr(struct btrfs_trans_handle *trans, |
| 2638 | struct btrfs_path *path, |
| 2639 | struct btrfs_disk_key *key, u64 bytenr, |
| 2640 | int slot, int level) |
| 2641 | { |
| 2642 | struct extent_buffer *lower; |
| 2643 | int nritems; |
| 2644 | int ret; |
| 2645 | |
| 2646 | BUG_ON(!path->nodes[level]); |
| 2647 | btrfs_assert_tree_write_locked(path->nodes[level]); |
| 2648 | lower = path->nodes[level]; |
| 2649 | nritems = btrfs_header_nritems(lower); |
| 2650 | BUG_ON(slot > nritems); |
| 2651 | BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(trans->fs_info)); |
| 2652 | if (slot != nritems) { |
| 2653 | if (level) { |
| 2654 | ret = btrfs_tree_mod_log_insert_move(lower, slot + 1, |
| 2655 | slot, nritems - slot); |
| 2656 | BUG_ON(ret < 0); |
| 2657 | } |
| 2658 | memmove_extent_buffer(lower, |
| 2659 | btrfs_node_key_ptr_offset(slot + 1), |
| 2660 | btrfs_node_key_ptr_offset(slot), |
| 2661 | (nritems - slot) * sizeof(struct btrfs_key_ptr)); |
| 2662 | } |
| 2663 | if (level) { |
| 2664 | ret = btrfs_tree_mod_log_insert_key(lower, slot, |
| 2665 | BTRFS_MOD_LOG_KEY_ADD, GFP_NOFS); |
| 2666 | BUG_ON(ret < 0); |
| 2667 | } |
| 2668 | btrfs_set_node_key(lower, key, slot); |
| 2669 | btrfs_set_node_blockptr(lower, slot, bytenr); |
| 2670 | WARN_ON(trans->transid == 0); |
| 2671 | btrfs_set_node_ptr_generation(lower, slot, trans->transid); |
| 2672 | btrfs_set_header_nritems(lower, nritems + 1); |
| 2673 | btrfs_mark_buffer_dirty(lower); |
| 2674 | } |
| 2675 | |
| 2676 | /* |
| 2677 | * split the node at the specified level in path in two. |
| 2678 | * The path is corrected to point to the appropriate node after the split |
| 2679 | * |
| 2680 | * Before splitting this tries to make some room in the node by pushing |
| 2681 | * left and right, if either one works, it returns right away. |
| 2682 | * |
| 2683 | * returns 0 on success and < 0 on failure |
| 2684 | */ |
| 2685 | static noinline int split_node(struct btrfs_trans_handle *trans, |
| 2686 | struct btrfs_root *root, |
| 2687 | struct btrfs_path *path, int level) |
| 2688 | { |
| 2689 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 2690 | struct extent_buffer *c; |
| 2691 | struct extent_buffer *split; |
| 2692 | struct btrfs_disk_key disk_key; |
| 2693 | int mid; |
| 2694 | int ret; |
| 2695 | u32 c_nritems; |
| 2696 | |
| 2697 | c = path->nodes[level]; |
| 2698 | WARN_ON(btrfs_header_generation(c) != trans->transid); |
| 2699 | if (c == root->node) { |
| 2700 | /* |
| 2701 | * trying to split the root, lets make a new one |
| 2702 | * |
| 2703 | * tree mod log: We don't log_removal old root in |
| 2704 | * insert_new_root, because that root buffer will be kept as a |
| 2705 | * normal node. We are going to log removal of half of the |
| 2706 | * elements below with btrfs_tree_mod_log_eb_copy(). We're |
| 2707 | * holding a tree lock on the buffer, which is why we cannot |
| 2708 | * race with other tree_mod_log users. |
| 2709 | */ |
| 2710 | ret = insert_new_root(trans, root, path, level + 1); |
| 2711 | if (ret) |
| 2712 | return ret; |
| 2713 | } else { |
| 2714 | ret = push_nodes_for_insert(trans, root, path, level); |
| 2715 | c = path->nodes[level]; |
| 2716 | if (!ret && btrfs_header_nritems(c) < |
| 2717 | BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) |
| 2718 | return 0; |
| 2719 | if (ret < 0) |
| 2720 | return ret; |
| 2721 | } |
| 2722 | |
| 2723 | c_nritems = btrfs_header_nritems(c); |
| 2724 | mid = (c_nritems + 1) / 2; |
| 2725 | btrfs_node_key(c, &disk_key, mid); |
| 2726 | |
| 2727 | split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
| 2728 | &disk_key, level, c->start, 0, |
| 2729 | BTRFS_NESTING_SPLIT); |
| 2730 | if (IS_ERR(split)) |
| 2731 | return PTR_ERR(split); |
| 2732 | |
| 2733 | root_add_used(root, fs_info->nodesize); |
| 2734 | ASSERT(btrfs_header_level(c) == level); |
| 2735 | |
| 2736 | ret = btrfs_tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid); |
| 2737 | if (ret) { |
| 2738 | btrfs_abort_transaction(trans, ret); |
| 2739 | return ret; |
| 2740 | } |
| 2741 | copy_extent_buffer(split, c, |
| 2742 | btrfs_node_key_ptr_offset(0), |
| 2743 | btrfs_node_key_ptr_offset(mid), |
| 2744 | (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); |
| 2745 | btrfs_set_header_nritems(split, c_nritems - mid); |
| 2746 | btrfs_set_header_nritems(c, mid); |
| 2747 | |
| 2748 | btrfs_mark_buffer_dirty(c); |
| 2749 | btrfs_mark_buffer_dirty(split); |
| 2750 | |
| 2751 | insert_ptr(trans, path, &disk_key, split->start, |
| 2752 | path->slots[level + 1] + 1, level + 1); |
| 2753 | |
| 2754 | if (path->slots[level] >= mid) { |
| 2755 | path->slots[level] -= mid; |
| 2756 | btrfs_tree_unlock(c); |
| 2757 | free_extent_buffer(c); |
| 2758 | path->nodes[level] = split; |
| 2759 | path->slots[level + 1] += 1; |
| 2760 | } else { |
| 2761 | btrfs_tree_unlock(split); |
| 2762 | free_extent_buffer(split); |
| 2763 | } |
| 2764 | return 0; |
| 2765 | } |
| 2766 | |
| 2767 | /* |
| 2768 | * how many bytes are required to store the items in a leaf. start |
| 2769 | * and nr indicate which items in the leaf to check. This totals up the |
| 2770 | * space used both by the item structs and the item data |
| 2771 | */ |
| 2772 | static int leaf_space_used(struct extent_buffer *l, int start, int nr) |
| 2773 | { |
| 2774 | int data_len; |
| 2775 | int nritems = btrfs_header_nritems(l); |
| 2776 | int end = min(nritems, start + nr) - 1; |
| 2777 | |
| 2778 | if (!nr) |
| 2779 | return 0; |
| 2780 | data_len = btrfs_item_offset(l, start) + btrfs_item_size(l, start); |
| 2781 | data_len = data_len - btrfs_item_offset(l, end); |
| 2782 | data_len += sizeof(struct btrfs_item) * nr; |
| 2783 | WARN_ON(data_len < 0); |
| 2784 | return data_len; |
| 2785 | } |
| 2786 | |
| 2787 | /* |
| 2788 | * The space between the end of the leaf items and |
| 2789 | * the start of the leaf data. IOW, how much room |
| 2790 | * the leaf has left for both items and data |
| 2791 | */ |
| 2792 | noinline int btrfs_leaf_free_space(struct extent_buffer *leaf) |
| 2793 | { |
| 2794 | struct btrfs_fs_info *fs_info = leaf->fs_info; |
| 2795 | int nritems = btrfs_header_nritems(leaf); |
| 2796 | int ret; |
| 2797 | |
| 2798 | ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems); |
| 2799 | if (ret < 0) { |
| 2800 | btrfs_crit(fs_info, |
| 2801 | "leaf free space ret %d, leaf data size %lu, used %d nritems %d", |
| 2802 | ret, |
| 2803 | (unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info), |
| 2804 | leaf_space_used(leaf, 0, nritems), nritems); |
| 2805 | } |
| 2806 | return ret; |
| 2807 | } |
| 2808 | |
| 2809 | /* |
| 2810 | * min slot controls the lowest index we're willing to push to the |
| 2811 | * right. We'll push up to and including min_slot, but no lower |
| 2812 | */ |
| 2813 | static noinline int __push_leaf_right(struct btrfs_path *path, |
| 2814 | int data_size, int empty, |
| 2815 | struct extent_buffer *right, |
| 2816 | int free_space, u32 left_nritems, |
| 2817 | u32 min_slot) |
| 2818 | { |
| 2819 | struct btrfs_fs_info *fs_info = right->fs_info; |
| 2820 | struct extent_buffer *left = path->nodes[0]; |
| 2821 | struct extent_buffer *upper = path->nodes[1]; |
| 2822 | struct btrfs_map_token token; |
| 2823 | struct btrfs_disk_key disk_key; |
| 2824 | int slot; |
| 2825 | u32 i; |
| 2826 | int push_space = 0; |
| 2827 | int push_items = 0; |
| 2828 | u32 nr; |
| 2829 | u32 right_nritems; |
| 2830 | u32 data_end; |
| 2831 | u32 this_item_size; |
| 2832 | |
| 2833 | if (empty) |
| 2834 | nr = 0; |
| 2835 | else |
| 2836 | nr = max_t(u32, 1, min_slot); |
| 2837 | |
| 2838 | if (path->slots[0] >= left_nritems) |
| 2839 | push_space += data_size; |
| 2840 | |
| 2841 | slot = path->slots[1]; |
| 2842 | i = left_nritems - 1; |
| 2843 | while (i >= nr) { |
| 2844 | if (!empty && push_items > 0) { |
| 2845 | if (path->slots[0] > i) |
| 2846 | break; |
| 2847 | if (path->slots[0] == i) { |
| 2848 | int space = btrfs_leaf_free_space(left); |
| 2849 | |
| 2850 | if (space + push_space * 2 > free_space) |
| 2851 | break; |
| 2852 | } |
| 2853 | } |
| 2854 | |
| 2855 | if (path->slots[0] == i) |
| 2856 | push_space += data_size; |
| 2857 | |
| 2858 | this_item_size = btrfs_item_size(left, i); |
| 2859 | if (this_item_size + sizeof(struct btrfs_item) + |
| 2860 | push_space > free_space) |
| 2861 | break; |
| 2862 | |
| 2863 | push_items++; |
| 2864 | push_space += this_item_size + sizeof(struct btrfs_item); |
| 2865 | if (i == 0) |
| 2866 | break; |
| 2867 | i--; |
| 2868 | } |
| 2869 | |
| 2870 | if (push_items == 0) |
| 2871 | goto out_unlock; |
| 2872 | |
| 2873 | WARN_ON(!empty && push_items == left_nritems); |
| 2874 | |
| 2875 | /* push left to right */ |
| 2876 | right_nritems = btrfs_header_nritems(right); |
| 2877 | |
| 2878 | push_space = btrfs_item_data_end(left, left_nritems - push_items); |
| 2879 | push_space -= leaf_data_end(left); |
| 2880 | |
| 2881 | /* make room in the right data area */ |
| 2882 | data_end = leaf_data_end(right); |
| 2883 | memmove_extent_buffer(right, |
| 2884 | BTRFS_LEAF_DATA_OFFSET + data_end - push_space, |
| 2885 | BTRFS_LEAF_DATA_OFFSET + data_end, |
| 2886 | BTRFS_LEAF_DATA_SIZE(fs_info) - data_end); |
| 2887 | |
| 2888 | /* copy from the left data area */ |
| 2889 | copy_extent_buffer(right, left, BTRFS_LEAF_DATA_OFFSET + |
| 2890 | BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, |
| 2891 | BTRFS_LEAF_DATA_OFFSET + leaf_data_end(left), |
| 2892 | push_space); |
| 2893 | |
| 2894 | memmove_extent_buffer(right, btrfs_item_nr_offset(push_items), |
| 2895 | btrfs_item_nr_offset(0), |
| 2896 | right_nritems * sizeof(struct btrfs_item)); |
| 2897 | |
| 2898 | /* copy the items from left to right */ |
| 2899 | copy_extent_buffer(right, left, btrfs_item_nr_offset(0), |
| 2900 | btrfs_item_nr_offset(left_nritems - push_items), |
| 2901 | push_items * sizeof(struct btrfs_item)); |
| 2902 | |
| 2903 | /* update the item pointers */ |
| 2904 | btrfs_init_map_token(&token, right); |
| 2905 | right_nritems += push_items; |
| 2906 | btrfs_set_header_nritems(right, right_nritems); |
| 2907 | push_space = BTRFS_LEAF_DATA_SIZE(fs_info); |
| 2908 | for (i = 0; i < right_nritems; i++) { |
| 2909 | push_space -= btrfs_token_item_size(&token, i); |
| 2910 | btrfs_set_token_item_offset(&token, i, push_space); |
| 2911 | } |
| 2912 | |
| 2913 | left_nritems -= push_items; |
| 2914 | btrfs_set_header_nritems(left, left_nritems); |
| 2915 | |
| 2916 | if (left_nritems) |
| 2917 | btrfs_mark_buffer_dirty(left); |
| 2918 | else |
| 2919 | btrfs_clean_tree_block(left); |
| 2920 | |
| 2921 | btrfs_mark_buffer_dirty(right); |
| 2922 | |
| 2923 | btrfs_item_key(right, &disk_key, 0); |
| 2924 | btrfs_set_node_key(upper, &disk_key, slot + 1); |
| 2925 | btrfs_mark_buffer_dirty(upper); |
| 2926 | |
| 2927 | /* then fixup the leaf pointer in the path */ |
| 2928 | if (path->slots[0] >= left_nritems) { |
| 2929 | path->slots[0] -= left_nritems; |
| 2930 | if (btrfs_header_nritems(path->nodes[0]) == 0) |
| 2931 | btrfs_clean_tree_block(path->nodes[0]); |
| 2932 | btrfs_tree_unlock(path->nodes[0]); |
| 2933 | free_extent_buffer(path->nodes[0]); |
| 2934 | path->nodes[0] = right; |
| 2935 | path->slots[1] += 1; |
| 2936 | } else { |
| 2937 | btrfs_tree_unlock(right); |
| 2938 | free_extent_buffer(right); |
| 2939 | } |
| 2940 | return 0; |
| 2941 | |
| 2942 | out_unlock: |
| 2943 | btrfs_tree_unlock(right); |
| 2944 | free_extent_buffer(right); |
| 2945 | return 1; |
| 2946 | } |
| 2947 | |
| 2948 | /* |
| 2949 | * push some data in the path leaf to the right, trying to free up at |
| 2950 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| 2951 | * |
| 2952 | * returns 1 if the push failed because the other node didn't have enough |
| 2953 | * room, 0 if everything worked out and < 0 if there were major errors. |
| 2954 | * |
| 2955 | * this will push starting from min_slot to the end of the leaf. It won't |
| 2956 | * push any slot lower than min_slot |
| 2957 | */ |
| 2958 | static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root |
| 2959 | *root, struct btrfs_path *path, |
| 2960 | int min_data_size, int data_size, |
| 2961 | int empty, u32 min_slot) |
| 2962 | { |
| 2963 | struct extent_buffer *left = path->nodes[0]; |
| 2964 | struct extent_buffer *right; |
| 2965 | struct extent_buffer *upper; |
| 2966 | int slot; |
| 2967 | int free_space; |
| 2968 | u32 left_nritems; |
| 2969 | int ret; |
| 2970 | |
| 2971 | if (!path->nodes[1]) |
| 2972 | return 1; |
| 2973 | |
| 2974 | slot = path->slots[1]; |
| 2975 | upper = path->nodes[1]; |
| 2976 | if (slot >= btrfs_header_nritems(upper) - 1) |
| 2977 | return 1; |
| 2978 | |
| 2979 | btrfs_assert_tree_write_locked(path->nodes[1]); |
| 2980 | |
| 2981 | right = btrfs_read_node_slot(upper, slot + 1); |
| 2982 | /* |
| 2983 | * slot + 1 is not valid or we fail to read the right node, |
| 2984 | * no big deal, just return. |
| 2985 | */ |
| 2986 | if (IS_ERR(right)) |
| 2987 | return 1; |
| 2988 | |
| 2989 | __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); |
| 2990 | |
| 2991 | free_space = btrfs_leaf_free_space(right); |
| 2992 | if (free_space < data_size) |
| 2993 | goto out_unlock; |
| 2994 | |
| 2995 | ret = btrfs_cow_block(trans, root, right, upper, |
| 2996 | slot + 1, &right, BTRFS_NESTING_RIGHT_COW); |
| 2997 | if (ret) |
| 2998 | goto out_unlock; |
| 2999 | |
| 3000 | left_nritems = btrfs_header_nritems(left); |
| 3001 | if (left_nritems == 0) |
| 3002 | goto out_unlock; |
| 3003 | |
| 3004 | if (check_sibling_keys(left, right)) { |
| 3005 | ret = -EUCLEAN; |
| 3006 | btrfs_tree_unlock(right); |
| 3007 | free_extent_buffer(right); |
| 3008 | return ret; |
| 3009 | } |
| 3010 | if (path->slots[0] == left_nritems && !empty) { |
| 3011 | /* Key greater than all keys in the leaf, right neighbor has |
| 3012 | * enough room for it and we're not emptying our leaf to delete |
| 3013 | * it, therefore use right neighbor to insert the new item and |
| 3014 | * no need to touch/dirty our left leaf. */ |
| 3015 | btrfs_tree_unlock(left); |
| 3016 | free_extent_buffer(left); |
| 3017 | path->nodes[0] = right; |
| 3018 | path->slots[0] = 0; |
| 3019 | path->slots[1]++; |
| 3020 | return 0; |
| 3021 | } |
| 3022 | |
| 3023 | return __push_leaf_right(path, min_data_size, empty, |
| 3024 | right, free_space, left_nritems, min_slot); |
| 3025 | out_unlock: |
| 3026 | btrfs_tree_unlock(right); |
| 3027 | free_extent_buffer(right); |
| 3028 | return 1; |
| 3029 | } |
| 3030 | |
| 3031 | /* |
| 3032 | * push some data in the path leaf to the left, trying to free up at |
| 3033 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| 3034 | * |
| 3035 | * max_slot can put a limit on how far into the leaf we'll push items. The |
| 3036 | * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the |
| 3037 | * items |
| 3038 | */ |
| 3039 | static noinline int __push_leaf_left(struct btrfs_path *path, int data_size, |
| 3040 | int empty, struct extent_buffer *left, |
| 3041 | int free_space, u32 right_nritems, |
| 3042 | u32 max_slot) |
| 3043 | { |
| 3044 | struct btrfs_fs_info *fs_info = left->fs_info; |
| 3045 | struct btrfs_disk_key disk_key; |
| 3046 | struct extent_buffer *right = path->nodes[0]; |
| 3047 | int i; |
| 3048 | int push_space = 0; |
| 3049 | int push_items = 0; |
| 3050 | u32 old_left_nritems; |
| 3051 | u32 nr; |
| 3052 | int ret = 0; |
| 3053 | u32 this_item_size; |
| 3054 | u32 old_left_item_size; |
| 3055 | struct btrfs_map_token token; |
| 3056 | |
| 3057 | if (empty) |
| 3058 | nr = min(right_nritems, max_slot); |
| 3059 | else |
| 3060 | nr = min(right_nritems - 1, max_slot); |
| 3061 | |
| 3062 | for (i = 0; i < nr; i++) { |
| 3063 | if (!empty && push_items > 0) { |
| 3064 | if (path->slots[0] < i) |
| 3065 | break; |
| 3066 | if (path->slots[0] == i) { |
| 3067 | int space = btrfs_leaf_free_space(right); |
| 3068 | |
| 3069 | if (space + push_space * 2 > free_space) |
| 3070 | break; |
| 3071 | } |
| 3072 | } |
| 3073 | |
| 3074 | if (path->slots[0] == i) |
| 3075 | push_space += data_size; |
| 3076 | |
| 3077 | this_item_size = btrfs_item_size(right, i); |
| 3078 | if (this_item_size + sizeof(struct btrfs_item) + push_space > |
| 3079 | free_space) |
| 3080 | break; |
| 3081 | |
| 3082 | push_items++; |
| 3083 | push_space += this_item_size + sizeof(struct btrfs_item); |
| 3084 | } |
| 3085 | |
| 3086 | if (push_items == 0) { |
| 3087 | ret = 1; |
| 3088 | goto out; |
| 3089 | } |
| 3090 | WARN_ON(!empty && push_items == btrfs_header_nritems(right)); |
| 3091 | |
| 3092 | /* push data from right to left */ |
| 3093 | copy_extent_buffer(left, right, |
| 3094 | btrfs_item_nr_offset(btrfs_header_nritems(left)), |
| 3095 | btrfs_item_nr_offset(0), |
| 3096 | push_items * sizeof(struct btrfs_item)); |
| 3097 | |
| 3098 | push_space = BTRFS_LEAF_DATA_SIZE(fs_info) - |
| 3099 | btrfs_item_offset(right, push_items - 1); |
| 3100 | |
| 3101 | copy_extent_buffer(left, right, BTRFS_LEAF_DATA_OFFSET + |
| 3102 | leaf_data_end(left) - push_space, |
| 3103 | BTRFS_LEAF_DATA_OFFSET + |
| 3104 | btrfs_item_offset(right, push_items - 1), |
| 3105 | push_space); |
| 3106 | old_left_nritems = btrfs_header_nritems(left); |
| 3107 | BUG_ON(old_left_nritems <= 0); |
| 3108 | |
| 3109 | btrfs_init_map_token(&token, left); |
| 3110 | old_left_item_size = btrfs_item_offset(left, old_left_nritems - 1); |
| 3111 | for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { |
| 3112 | u32 ioff; |
| 3113 | |
| 3114 | ioff = btrfs_token_item_offset(&token, i); |
| 3115 | btrfs_set_token_item_offset(&token, i, |
| 3116 | ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size)); |
| 3117 | } |
| 3118 | btrfs_set_header_nritems(left, old_left_nritems + push_items); |
| 3119 | |
| 3120 | /* fixup right node */ |
| 3121 | if (push_items > right_nritems) |
| 3122 | WARN(1, KERN_CRIT "push items %d nr %u\n", push_items, |
| 3123 | right_nritems); |
| 3124 | |
| 3125 | if (push_items < right_nritems) { |
| 3126 | push_space = btrfs_item_offset(right, push_items - 1) - |
| 3127 | leaf_data_end(right); |
| 3128 | memmove_extent_buffer(right, BTRFS_LEAF_DATA_OFFSET + |
| 3129 | BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, |
| 3130 | BTRFS_LEAF_DATA_OFFSET + |
| 3131 | leaf_data_end(right), push_space); |
| 3132 | |
| 3133 | memmove_extent_buffer(right, btrfs_item_nr_offset(0), |
| 3134 | btrfs_item_nr_offset(push_items), |
| 3135 | (btrfs_header_nritems(right) - push_items) * |
| 3136 | sizeof(struct btrfs_item)); |
| 3137 | } |
| 3138 | |
| 3139 | btrfs_init_map_token(&token, right); |
| 3140 | right_nritems -= push_items; |
| 3141 | btrfs_set_header_nritems(right, right_nritems); |
| 3142 | push_space = BTRFS_LEAF_DATA_SIZE(fs_info); |
| 3143 | for (i = 0; i < right_nritems; i++) { |
| 3144 | push_space = push_space - btrfs_token_item_size(&token, i); |
| 3145 | btrfs_set_token_item_offset(&token, i, push_space); |
| 3146 | } |
| 3147 | |
| 3148 | btrfs_mark_buffer_dirty(left); |
| 3149 | if (right_nritems) |
| 3150 | btrfs_mark_buffer_dirty(right); |
| 3151 | else |
| 3152 | btrfs_clean_tree_block(right); |
| 3153 | |
| 3154 | btrfs_item_key(right, &disk_key, 0); |
| 3155 | fixup_low_keys(path, &disk_key, 1); |
| 3156 | |
| 3157 | /* then fixup the leaf pointer in the path */ |
| 3158 | if (path->slots[0] < push_items) { |
| 3159 | path->slots[0] += old_left_nritems; |
| 3160 | btrfs_tree_unlock(path->nodes[0]); |
| 3161 | free_extent_buffer(path->nodes[0]); |
| 3162 | path->nodes[0] = left; |
| 3163 | path->slots[1] -= 1; |
| 3164 | } else { |
| 3165 | btrfs_tree_unlock(left); |
| 3166 | free_extent_buffer(left); |
| 3167 | path->slots[0] -= push_items; |
| 3168 | } |
| 3169 | BUG_ON(path->slots[0] < 0); |
| 3170 | return ret; |
| 3171 | out: |
| 3172 | btrfs_tree_unlock(left); |
| 3173 | free_extent_buffer(left); |
| 3174 | return ret; |
| 3175 | } |
| 3176 | |
| 3177 | /* |
| 3178 | * push some data in the path leaf to the left, trying to free up at |
| 3179 | * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| 3180 | * |
| 3181 | * max_slot can put a limit on how far into the leaf we'll push items. The |
| 3182 | * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the |
| 3183 | * items |
| 3184 | */ |
| 3185 | static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root |
| 3186 | *root, struct btrfs_path *path, int min_data_size, |
| 3187 | int data_size, int empty, u32 max_slot) |
| 3188 | { |
| 3189 | struct extent_buffer *right = path->nodes[0]; |
| 3190 | struct extent_buffer *left; |
| 3191 | int slot; |
| 3192 | int free_space; |
| 3193 | u32 right_nritems; |
| 3194 | int ret = 0; |
| 3195 | |
| 3196 | slot = path->slots[1]; |
| 3197 | if (slot == 0) |
| 3198 | return 1; |
| 3199 | if (!path->nodes[1]) |
| 3200 | return 1; |
| 3201 | |
| 3202 | right_nritems = btrfs_header_nritems(right); |
| 3203 | if (right_nritems == 0) |
| 3204 | return 1; |
| 3205 | |
| 3206 | btrfs_assert_tree_write_locked(path->nodes[1]); |
| 3207 | |
| 3208 | left = btrfs_read_node_slot(path->nodes[1], slot - 1); |
| 3209 | /* |
| 3210 | * slot - 1 is not valid or we fail to read the left node, |
| 3211 | * no big deal, just return. |
| 3212 | */ |
| 3213 | if (IS_ERR(left)) |
| 3214 | return 1; |
| 3215 | |
| 3216 | __btrfs_tree_lock(left, BTRFS_NESTING_LEFT); |
| 3217 | |
| 3218 | free_space = btrfs_leaf_free_space(left); |
| 3219 | if (free_space < data_size) { |
| 3220 | ret = 1; |
| 3221 | goto out; |
| 3222 | } |
| 3223 | |
| 3224 | ret = btrfs_cow_block(trans, root, left, |
| 3225 | path->nodes[1], slot - 1, &left, |
| 3226 | BTRFS_NESTING_LEFT_COW); |
| 3227 | if (ret) { |
| 3228 | /* we hit -ENOSPC, but it isn't fatal here */ |
| 3229 | if (ret == -ENOSPC) |
| 3230 | ret = 1; |
| 3231 | goto out; |
| 3232 | } |
| 3233 | |
| 3234 | if (check_sibling_keys(left, right)) { |
| 3235 | ret = -EUCLEAN; |
| 3236 | goto out; |
| 3237 | } |
| 3238 | return __push_leaf_left(path, min_data_size, |
| 3239 | empty, left, free_space, right_nritems, |
| 3240 | max_slot); |
| 3241 | out: |
| 3242 | btrfs_tree_unlock(left); |
| 3243 | free_extent_buffer(left); |
| 3244 | return ret; |
| 3245 | } |
| 3246 | |
| 3247 | /* |
| 3248 | * split the path's leaf in two, making sure there is at least data_size |
| 3249 | * available for the resulting leaf level of the path. |
| 3250 | */ |
| 3251 | static noinline void copy_for_split(struct btrfs_trans_handle *trans, |
| 3252 | struct btrfs_path *path, |
| 3253 | struct extent_buffer *l, |
| 3254 | struct extent_buffer *right, |
| 3255 | int slot, int mid, int nritems) |
| 3256 | { |
| 3257 | struct btrfs_fs_info *fs_info = trans->fs_info; |
| 3258 | int data_copy_size; |
| 3259 | int rt_data_off; |
| 3260 | int i; |
| 3261 | struct btrfs_disk_key disk_key; |
| 3262 | struct btrfs_map_token token; |
| 3263 | |
| 3264 | nritems = nritems - mid; |
| 3265 | btrfs_set_header_nritems(right, nritems); |
| 3266 | data_copy_size = btrfs_item_data_end(l, mid) - leaf_data_end(l); |
| 3267 | |
| 3268 | copy_extent_buffer(right, l, btrfs_item_nr_offset(0), |
| 3269 | btrfs_item_nr_offset(mid), |
| 3270 | nritems * sizeof(struct btrfs_item)); |
| 3271 | |
| 3272 | copy_extent_buffer(right, l, |
| 3273 | BTRFS_LEAF_DATA_OFFSET + BTRFS_LEAF_DATA_SIZE(fs_info) - |
| 3274 | data_copy_size, BTRFS_LEAF_DATA_OFFSET + |
| 3275 | leaf_data_end(l), data_copy_size); |
| 3276 | |
| 3277 | rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_data_end(l, mid); |
| 3278 | |
| 3279 | btrfs_init_map_token(&token, right); |
| 3280 | for (i = 0; i < nritems; i++) { |
| 3281 | u32 ioff; |
| 3282 | |
| 3283 | ioff = btrfs_token_item_offset(&token, i); |
| 3284 | btrfs_set_token_item_offset(&token, i, ioff + rt_data_off); |
| 3285 | } |
| 3286 | |
| 3287 | btrfs_set_header_nritems(l, mid); |
| 3288 | btrfs_item_key(right, &disk_key, 0); |
| 3289 | insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1); |
| 3290 | |
| 3291 | btrfs_mark_buffer_dirty(right); |
| 3292 | btrfs_mark_buffer_dirty(l); |
| 3293 | BUG_ON(path->slots[0] != slot); |
| 3294 | |
| 3295 | if (mid <= slot) { |
| 3296 | btrfs_tree_unlock(path->nodes[0]); |
| 3297 | free_extent_buffer(path->nodes[0]); |
| 3298 | path->nodes[0] = right; |
| 3299 | path->slots[0] -= mid; |
| 3300 | path->slots[1] += 1; |
| 3301 | } else { |
| 3302 | btrfs_tree_unlock(right); |
| 3303 | free_extent_buffer(right); |
| 3304 | } |
| 3305 | |
| 3306 | BUG_ON(path->slots[0] < 0); |
| 3307 | } |
| 3308 | |
| 3309 | /* |
| 3310 | * double splits happen when we need to insert a big item in the middle |
| 3311 | * of a leaf. A double split can leave us with 3 mostly empty leaves: |
| 3312 | * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ] |
| 3313 | * A B C |
| 3314 | * |
| 3315 | * We avoid this by trying to push the items on either side of our target |
| 3316 | * into the adjacent leaves. If all goes well we can avoid the double split |
| 3317 | * completely. |
| 3318 | */ |
| 3319 | static noinline int push_for_double_split(struct btrfs_trans_handle *trans, |
| 3320 | struct btrfs_root *root, |
| 3321 | struct btrfs_path *path, |
| 3322 | int data_size) |
| 3323 | { |
| 3324 | int ret; |
| 3325 | int progress = 0; |
| 3326 | int slot; |
| 3327 | u32 nritems; |
| 3328 | int space_needed = data_size; |
| 3329 | |
| 3330 | slot = path->slots[0]; |
| 3331 | if (slot < btrfs_header_nritems(path->nodes[0])) |
| 3332 | space_needed -= btrfs_leaf_free_space(path->nodes[0]); |
| 3333 | |
| 3334 | /* |
| 3335 | * try to push all the items after our slot into the |
| 3336 | * right leaf |
| 3337 | */ |
| 3338 | ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot); |
| 3339 | if (ret < 0) |
| 3340 | return ret; |
| 3341 | |
| 3342 | if (ret == 0) |
| 3343 | progress++; |
| 3344 | |
| 3345 | nritems = btrfs_header_nritems(path->nodes[0]); |
| 3346 | /* |
| 3347 | * our goal is to get our slot at the start or end of a leaf. If |
| 3348 | * we've done so we're done |
| 3349 | */ |
| 3350 | if (path->slots[0] == 0 || path->slots[0] == nritems) |
| 3351 | return 0; |
| 3352 | |
| 3353 | if (btrfs_leaf_free_space(path->nodes[0]) >= data_size) |
| 3354 | return 0; |
| 3355 | |
| 3356 | /* try to push all the items before our slot into the next leaf */ |
| 3357 | slot = path->slots[0]; |
| 3358 | space_needed = data_size; |
| 3359 | if (slot > 0) |
| 3360 | space_needed -= btrfs_leaf_free_space(path->nodes[0]); |
| 3361 | ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot); |
| 3362 | if (ret < 0) |
| 3363 | return ret; |
| 3364 | |
| 3365 | if (ret == 0) |
| 3366 | progress++; |
| 3367 | |
| 3368 | if (progress) |
| 3369 | return 0; |
| 3370 | return 1; |
| 3371 | } |
| 3372 | |
| 3373 | /* |
| 3374 | * split the path's leaf in two, making sure there is at least data_size |
| 3375 | * available for the resulting leaf level of the path. |
| 3376 | * |
| 3377 | * returns 0 if all went well and < 0 on failure. |
| 3378 | */ |
| 3379 | static noinline int split_leaf(struct btrfs_trans_handle *trans, |
| 3380 | struct btrfs_root *root, |
| 3381 | const struct btrfs_key *ins_key, |
| 3382 | struct btrfs_path *path, int data_size, |
| 3383 | int extend) |
| 3384 | { |
| 3385 | struct btrfs_disk_key disk_key; |
| 3386 | struct extent_buffer *l; |
| 3387 | u32 nritems; |
| 3388 | int mid; |
| 3389 | int slot; |
| 3390 | struct extent_buffer *right; |
| 3391 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 3392 | int ret = 0; |
| 3393 | int wret; |
| 3394 | int split; |
| 3395 | int num_doubles = 0; |
| 3396 | int tried_avoid_double = 0; |
| 3397 | |
| 3398 | l = path->nodes[0]; |
| 3399 | slot = path->slots[0]; |
| 3400 | if (extend && data_size + btrfs_item_size(l, slot) + |
| 3401 | sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info)) |
| 3402 | return -EOVERFLOW; |
| 3403 | |
| 3404 | /* first try to make some room by pushing left and right */ |
| 3405 | if (data_size && path->nodes[1]) { |
| 3406 | int space_needed = data_size; |
| 3407 | |
| 3408 | if (slot < btrfs_header_nritems(l)) |
| 3409 | space_needed -= btrfs_leaf_free_space(l); |
| 3410 | |
| 3411 | wret = push_leaf_right(trans, root, path, space_needed, |
| 3412 | space_needed, 0, 0); |
| 3413 | if (wret < 0) |
| 3414 | return wret; |
| 3415 | if (wret) { |
| 3416 | space_needed = data_size; |
| 3417 | if (slot > 0) |
| 3418 | space_needed -= btrfs_leaf_free_space(l); |
| 3419 | wret = push_leaf_left(trans, root, path, space_needed, |
| 3420 | space_needed, 0, (u32)-1); |
| 3421 | if (wret < 0) |
| 3422 | return wret; |
| 3423 | } |
| 3424 | l = path->nodes[0]; |
| 3425 | |
| 3426 | /* did the pushes work? */ |
| 3427 | if (btrfs_leaf_free_space(l) >= data_size) |
| 3428 | return 0; |
| 3429 | } |
| 3430 | |
| 3431 | if (!path->nodes[1]) { |
| 3432 | ret = insert_new_root(trans, root, path, 1); |
| 3433 | if (ret) |
| 3434 | return ret; |
| 3435 | } |
| 3436 | again: |
| 3437 | split = 1; |
| 3438 | l = path->nodes[0]; |
| 3439 | slot = path->slots[0]; |
| 3440 | nritems = btrfs_header_nritems(l); |
| 3441 | mid = (nritems + 1) / 2; |
| 3442 | |
| 3443 | if (mid <= slot) { |
| 3444 | if (nritems == 1 || |
| 3445 | leaf_space_used(l, mid, nritems - mid) + data_size > |
| 3446 | BTRFS_LEAF_DATA_SIZE(fs_info)) { |
| 3447 | if (slot >= nritems) { |
| 3448 | split = 0; |
| 3449 | } else { |
| 3450 | mid = slot; |
| 3451 | if (mid != nritems && |
| 3452 | leaf_space_used(l, mid, nritems - mid) + |
| 3453 | data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { |
| 3454 | if (data_size && !tried_avoid_double) |
| 3455 | goto push_for_double; |
| 3456 | split = 2; |
| 3457 | } |
| 3458 | } |
| 3459 | } |
| 3460 | } else { |
| 3461 | if (leaf_space_used(l, 0, mid) + data_size > |
| 3462 | BTRFS_LEAF_DATA_SIZE(fs_info)) { |
| 3463 | if (!extend && data_size && slot == 0) { |
| 3464 | split = 0; |
| 3465 | } else if ((extend || !data_size) && slot == 0) { |
| 3466 | mid = 1; |
| 3467 | } else { |
| 3468 | mid = slot; |
| 3469 | if (mid != nritems && |
| 3470 | leaf_space_used(l, mid, nritems - mid) + |
| 3471 | data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { |
| 3472 | if (data_size && !tried_avoid_double) |
| 3473 | goto push_for_double; |
| 3474 | split = 2; |
| 3475 | } |
| 3476 | } |
| 3477 | } |
| 3478 | } |
| 3479 | |
| 3480 | if (split == 0) |
| 3481 | btrfs_cpu_key_to_disk(&disk_key, ins_key); |
| 3482 | else |
| 3483 | btrfs_item_key(l, &disk_key, mid); |
| 3484 | |
| 3485 | /* |
| 3486 | * We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double |
| 3487 | * split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES |
| 3488 | * subclasses, which is 8 at the time of this patch, and we've maxed it |
| 3489 | * out. In the future we could add a |
| 3490 | * BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just |
| 3491 | * use BTRFS_NESTING_NEW_ROOT. |
| 3492 | */ |
| 3493 | right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
| 3494 | &disk_key, 0, l->start, 0, |
| 3495 | num_doubles ? BTRFS_NESTING_NEW_ROOT : |
| 3496 | BTRFS_NESTING_SPLIT); |
| 3497 | if (IS_ERR(right)) |
| 3498 | return PTR_ERR(right); |
| 3499 | |
| 3500 | root_add_used(root, fs_info->nodesize); |
| 3501 | |
| 3502 | if (split == 0) { |
| 3503 | if (mid <= slot) { |
| 3504 | btrfs_set_header_nritems(right, 0); |
| 3505 | insert_ptr(trans, path, &disk_key, |
| 3506 | right->start, path->slots[1] + 1, 1); |
| 3507 | btrfs_tree_unlock(path->nodes[0]); |
| 3508 | free_extent_buffer(path->nodes[0]); |
| 3509 | path->nodes[0] = right; |
| 3510 | path->slots[0] = 0; |
| 3511 | path->slots[1] += 1; |
| 3512 | } else { |
| 3513 | btrfs_set_header_nritems(right, 0); |
| 3514 | insert_ptr(trans, path, &disk_key, |
| 3515 | right->start, path->slots[1], 1); |
| 3516 | btrfs_tree_unlock(path->nodes[0]); |
| 3517 | free_extent_buffer(path->nodes[0]); |
| 3518 | path->nodes[0] = right; |
| 3519 | path->slots[0] = 0; |
| 3520 | if (path->slots[1] == 0) |
| 3521 | fixup_low_keys(path, &disk_key, 1); |
| 3522 | } |
| 3523 | /* |
| 3524 | * We create a new leaf 'right' for the required ins_len and |
| 3525 | * we'll do btrfs_mark_buffer_dirty() on this leaf after copying |
| 3526 | * the content of ins_len to 'right'. |
| 3527 | */ |
| 3528 | return ret; |
| 3529 | } |
| 3530 | |
| 3531 | copy_for_split(trans, path, l, right, slot, mid, nritems); |
| 3532 | |
| 3533 | if (split == 2) { |
| 3534 | BUG_ON(num_doubles != 0); |
| 3535 | num_doubles++; |
| 3536 | goto again; |
| 3537 | } |
| 3538 | |
| 3539 | return 0; |
| 3540 | |
| 3541 | push_for_double: |
| 3542 | push_for_double_split(trans, root, path, data_size); |
| 3543 | tried_avoid_double = 1; |
| 3544 | if (btrfs_leaf_free_space(path->nodes[0]) >= data_size) |
| 3545 | return 0; |
| 3546 | goto again; |
| 3547 | } |
| 3548 | |
| 3549 | static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, |
| 3550 | struct btrfs_root *root, |
| 3551 | struct btrfs_path *path, int ins_len) |
| 3552 | { |
| 3553 | struct btrfs_key key; |
| 3554 | struct extent_buffer *leaf; |
| 3555 | struct btrfs_file_extent_item *fi; |
| 3556 | u64 extent_len = 0; |
| 3557 | u32 item_size; |
| 3558 | int ret; |
| 3559 | |
| 3560 | leaf = path->nodes[0]; |
| 3561 | btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); |
| 3562 | |
| 3563 | BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY && |
| 3564 | key.type != BTRFS_EXTENT_CSUM_KEY); |
| 3565 | |
| 3566 | if (btrfs_leaf_free_space(leaf) >= ins_len) |
| 3567 | return 0; |
| 3568 | |
| 3569 | item_size = btrfs_item_size(leaf, path->slots[0]); |
| 3570 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
| 3571 | fi = btrfs_item_ptr(leaf, path->slots[0], |
| 3572 | struct btrfs_file_extent_item); |
| 3573 | extent_len = btrfs_file_extent_num_bytes(leaf, fi); |
| 3574 | } |
| 3575 | btrfs_release_path(path); |
| 3576 | |
| 3577 | path->keep_locks = 1; |
| 3578 | path->search_for_split = 1; |
| 3579 | ret = btrfs_search_slot(trans, root, &key, path, 0, 1); |
| 3580 | path->search_for_split = 0; |
| 3581 | if (ret > 0) |
| 3582 | ret = -EAGAIN; |
| 3583 | if (ret < 0) |
| 3584 | goto err; |
| 3585 | |
| 3586 | ret = -EAGAIN; |
| 3587 | leaf = path->nodes[0]; |
| 3588 | /* if our item isn't there, return now */ |
| 3589 | if (item_size != btrfs_item_size(leaf, path->slots[0])) |
| 3590 | goto err; |
| 3591 | |
| 3592 | /* the leaf has changed, it now has room. return now */ |
| 3593 | if (btrfs_leaf_free_space(path->nodes[0]) >= ins_len) |
| 3594 | goto err; |
| 3595 | |
| 3596 | if (key.type == BTRFS_EXTENT_DATA_KEY) { |
| 3597 | fi = btrfs_item_ptr(leaf, path->slots[0], |
| 3598 | struct btrfs_file_extent_item); |
| 3599 | if (extent_len != btrfs_file_extent_num_bytes(leaf, fi)) |
| 3600 | goto err; |
| 3601 | } |
| 3602 | |
| 3603 | ret = split_leaf(trans, root, &key, path, ins_len, 1); |
| 3604 | if (ret) |
| 3605 | goto err; |
| 3606 | |
| 3607 | path->keep_locks = 0; |
| 3608 | btrfs_unlock_up_safe(path, 1); |
| 3609 | return 0; |
| 3610 | err: |
| 3611 | path->keep_locks = 0; |
| 3612 | return ret; |
| 3613 | } |
| 3614 | |
| 3615 | static noinline int split_item(struct btrfs_path *path, |
| 3616 | const struct btrfs_key *new_key, |
| 3617 | unsigned long split_offset) |
| 3618 | { |
| 3619 | struct extent_buffer *leaf; |
| 3620 | int orig_slot, slot; |
| 3621 | char *buf; |
| 3622 | u32 nritems; |
| 3623 | u32 item_size; |
| 3624 | u32 orig_offset; |
| 3625 | struct btrfs_disk_key disk_key; |
| 3626 | |
| 3627 | leaf = path->nodes[0]; |
| 3628 | BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item)); |
| 3629 | |
| 3630 | orig_slot = path->slots[0]; |
| 3631 | orig_offset = btrfs_item_offset(leaf, path->slots[0]); |
| 3632 | item_size = btrfs_item_size(leaf, path->slots[0]); |
| 3633 | |
| 3634 | buf = kmalloc(item_size, GFP_NOFS); |
| 3635 | if (!buf) |
| 3636 | return -ENOMEM; |
| 3637 | |
| 3638 | read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, |
| 3639 | path->slots[0]), item_size); |
| 3640 | |
| 3641 | slot = path->slots[0] + 1; |
| 3642 | nritems = btrfs_header_nritems(leaf); |
| 3643 | if (slot != nritems) { |
| 3644 | /* shift the items */ |
| 3645 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1), |
| 3646 | btrfs_item_nr_offset(slot), |
| 3647 | (nritems - slot) * sizeof(struct btrfs_item)); |
| 3648 | } |
| 3649 | |
| 3650 | btrfs_cpu_key_to_disk(&disk_key, new_key); |
| 3651 | btrfs_set_item_key(leaf, &disk_key, slot); |
| 3652 | |
| 3653 | btrfs_set_item_offset(leaf, slot, orig_offset); |
| 3654 | btrfs_set_item_size(leaf, slot, item_size - split_offset); |
| 3655 | |
| 3656 | btrfs_set_item_offset(leaf, orig_slot, |
| 3657 | orig_offset + item_size - split_offset); |
| 3658 | btrfs_set_item_size(leaf, orig_slot, split_offset); |
| 3659 | |
| 3660 | btrfs_set_header_nritems(leaf, nritems + 1); |
| 3661 | |
| 3662 | /* write the data for the start of the original item */ |
| 3663 | write_extent_buffer(leaf, buf, |
| 3664 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
| 3665 | split_offset); |
| 3666 | |
| 3667 | /* write the data for the new item */ |
| 3668 | write_extent_buffer(leaf, buf + split_offset, |
| 3669 | btrfs_item_ptr_offset(leaf, slot), |
| 3670 | item_size - split_offset); |
| 3671 | btrfs_mark_buffer_dirty(leaf); |
| 3672 | |
| 3673 | BUG_ON(btrfs_leaf_free_space(leaf) < 0); |
| 3674 | kfree(buf); |
| 3675 | return 0; |
| 3676 | } |
| 3677 | |
| 3678 | /* |
| 3679 | * This function splits a single item into two items, |
| 3680 | * giving 'new_key' to the new item and splitting the |
| 3681 | * old one at split_offset (from the start of the item). |
| 3682 | * |
| 3683 | * The path may be released by this operation. After |
| 3684 | * the split, the path is pointing to the old item. The |
| 3685 | * new item is going to be in the same node as the old one. |
| 3686 | * |
| 3687 | * Note, the item being split must be smaller enough to live alone on |
| 3688 | * a tree block with room for one extra struct btrfs_item |
| 3689 | * |
| 3690 | * This allows us to split the item in place, keeping a lock on the |
| 3691 | * leaf the entire time. |
| 3692 | */ |
| 3693 | int btrfs_split_item(struct btrfs_trans_handle *trans, |
| 3694 | struct btrfs_root *root, |
| 3695 | struct btrfs_path *path, |
| 3696 | const struct btrfs_key *new_key, |
| 3697 | unsigned long split_offset) |
| 3698 | { |
| 3699 | int ret; |
| 3700 | ret = setup_leaf_for_split(trans, root, path, |
| 3701 | sizeof(struct btrfs_item)); |
| 3702 | if (ret) |
| 3703 | return ret; |
| 3704 | |
| 3705 | ret = split_item(path, new_key, split_offset); |
| 3706 | return ret; |
| 3707 | } |
| 3708 | |
| 3709 | /* |
| 3710 | * make the item pointed to by the path smaller. new_size indicates |
| 3711 | * how small to make it, and from_end tells us if we just chop bytes |
| 3712 | * off the end of the item or if we shift the item to chop bytes off |
| 3713 | * the front. |
| 3714 | */ |
| 3715 | void btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end) |
| 3716 | { |
| 3717 | int slot; |
| 3718 | struct extent_buffer *leaf; |
| 3719 | u32 nritems; |
| 3720 | unsigned int data_end; |
| 3721 | unsigned int old_data_start; |
| 3722 | unsigned int old_size; |
| 3723 | unsigned int size_diff; |
| 3724 | int i; |
| 3725 | struct btrfs_map_token token; |
| 3726 | |
| 3727 | leaf = path->nodes[0]; |
| 3728 | slot = path->slots[0]; |
| 3729 | |
| 3730 | old_size = btrfs_item_size(leaf, slot); |
| 3731 | if (old_size == new_size) |
| 3732 | return; |
| 3733 | |
| 3734 | nritems = btrfs_header_nritems(leaf); |
| 3735 | data_end = leaf_data_end(leaf); |
| 3736 | |
| 3737 | old_data_start = btrfs_item_offset(leaf, slot); |
| 3738 | |
| 3739 | size_diff = old_size - new_size; |
| 3740 | |
| 3741 | BUG_ON(slot < 0); |
| 3742 | BUG_ON(slot >= nritems); |
| 3743 | |
| 3744 | /* |
| 3745 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
| 3746 | */ |
| 3747 | /* first correct the data pointers */ |
| 3748 | btrfs_init_map_token(&token, leaf); |
| 3749 | for (i = slot; i < nritems; i++) { |
| 3750 | u32 ioff; |
| 3751 | |
| 3752 | ioff = btrfs_token_item_offset(&token, i); |
| 3753 | btrfs_set_token_item_offset(&token, i, ioff + size_diff); |
| 3754 | } |
| 3755 | |
| 3756 | /* shift the data */ |
| 3757 | if (from_end) { |
| 3758 | memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
| 3759 | data_end + size_diff, BTRFS_LEAF_DATA_OFFSET + |
| 3760 | data_end, old_data_start + new_size - data_end); |
| 3761 | } else { |
| 3762 | struct btrfs_disk_key disk_key; |
| 3763 | u64 offset; |
| 3764 | |
| 3765 | btrfs_item_key(leaf, &disk_key, slot); |
| 3766 | |
| 3767 | if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) { |
| 3768 | unsigned long ptr; |
| 3769 | struct btrfs_file_extent_item *fi; |
| 3770 | |
| 3771 | fi = btrfs_item_ptr(leaf, slot, |
| 3772 | struct btrfs_file_extent_item); |
| 3773 | fi = (struct btrfs_file_extent_item *)( |
| 3774 | (unsigned long)fi - size_diff); |
| 3775 | |
| 3776 | if (btrfs_file_extent_type(leaf, fi) == |
| 3777 | BTRFS_FILE_EXTENT_INLINE) { |
| 3778 | ptr = btrfs_item_ptr_offset(leaf, slot); |
| 3779 | memmove_extent_buffer(leaf, ptr, |
| 3780 | (unsigned long)fi, |
| 3781 | BTRFS_FILE_EXTENT_INLINE_DATA_START); |
| 3782 | } |
| 3783 | } |
| 3784 | |
| 3785 | memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
| 3786 | data_end + size_diff, BTRFS_LEAF_DATA_OFFSET + |
| 3787 | data_end, old_data_start - data_end); |
| 3788 | |
| 3789 | offset = btrfs_disk_key_offset(&disk_key); |
| 3790 | btrfs_set_disk_key_offset(&disk_key, offset + size_diff); |
| 3791 | btrfs_set_item_key(leaf, &disk_key, slot); |
| 3792 | if (slot == 0) |
| 3793 | fixup_low_keys(path, &disk_key, 1); |
| 3794 | } |
| 3795 | |
| 3796 | btrfs_set_item_size(leaf, slot, new_size); |
| 3797 | btrfs_mark_buffer_dirty(leaf); |
| 3798 | |
| 3799 | if (btrfs_leaf_free_space(leaf) < 0) { |
| 3800 | btrfs_print_leaf(leaf); |
| 3801 | BUG(); |
| 3802 | } |
| 3803 | } |
| 3804 | |
| 3805 | /* |
| 3806 | * make the item pointed to by the path bigger, data_size is the added size. |
| 3807 | */ |
| 3808 | void btrfs_extend_item(struct btrfs_path *path, u32 data_size) |
| 3809 | { |
| 3810 | int slot; |
| 3811 | struct extent_buffer *leaf; |
| 3812 | u32 nritems; |
| 3813 | unsigned int data_end; |
| 3814 | unsigned int old_data; |
| 3815 | unsigned int old_size; |
| 3816 | int i; |
| 3817 | struct btrfs_map_token token; |
| 3818 | |
| 3819 | leaf = path->nodes[0]; |
| 3820 | |
| 3821 | nritems = btrfs_header_nritems(leaf); |
| 3822 | data_end = leaf_data_end(leaf); |
| 3823 | |
| 3824 | if (btrfs_leaf_free_space(leaf) < data_size) { |
| 3825 | btrfs_print_leaf(leaf); |
| 3826 | BUG(); |
| 3827 | } |
| 3828 | slot = path->slots[0]; |
| 3829 | old_data = btrfs_item_data_end(leaf, slot); |
| 3830 | |
| 3831 | BUG_ON(slot < 0); |
| 3832 | if (slot >= nritems) { |
| 3833 | btrfs_print_leaf(leaf); |
| 3834 | btrfs_crit(leaf->fs_info, "slot %d too large, nritems %d", |
| 3835 | slot, nritems); |
| 3836 | BUG(); |
| 3837 | } |
| 3838 | |
| 3839 | /* |
| 3840 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
| 3841 | */ |
| 3842 | /* first correct the data pointers */ |
| 3843 | btrfs_init_map_token(&token, leaf); |
| 3844 | for (i = slot; i < nritems; i++) { |
| 3845 | u32 ioff; |
| 3846 | |
| 3847 | ioff = btrfs_token_item_offset(&token, i); |
| 3848 | btrfs_set_token_item_offset(&token, i, ioff - data_size); |
| 3849 | } |
| 3850 | |
| 3851 | /* shift the data */ |
| 3852 | memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
| 3853 | data_end - data_size, BTRFS_LEAF_DATA_OFFSET + |
| 3854 | data_end, old_data - data_end); |
| 3855 | |
| 3856 | data_end = old_data; |
| 3857 | old_size = btrfs_item_size(leaf, slot); |
| 3858 | btrfs_set_item_size(leaf, slot, old_size + data_size); |
| 3859 | btrfs_mark_buffer_dirty(leaf); |
| 3860 | |
| 3861 | if (btrfs_leaf_free_space(leaf) < 0) { |
| 3862 | btrfs_print_leaf(leaf); |
| 3863 | BUG(); |
| 3864 | } |
| 3865 | } |
| 3866 | |
| 3867 | /** |
| 3868 | * setup_items_for_insert - Helper called before inserting one or more items |
| 3869 | * to a leaf. Main purpose is to save stack depth by doing the bulk of the work |
| 3870 | * in a function that doesn't call btrfs_search_slot |
| 3871 | * |
| 3872 | * @root: root we are inserting items to |
| 3873 | * @path: points to the leaf/slot where we are going to insert new items |
| 3874 | * @batch: information about the batch of items to insert |
| 3875 | */ |
| 3876 | static void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path, |
| 3877 | const struct btrfs_item_batch *batch) |
| 3878 | { |
| 3879 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 3880 | int i; |
| 3881 | u32 nritems; |
| 3882 | unsigned int data_end; |
| 3883 | struct btrfs_disk_key disk_key; |
| 3884 | struct extent_buffer *leaf; |
| 3885 | int slot; |
| 3886 | struct btrfs_map_token token; |
| 3887 | u32 total_size; |
| 3888 | |
| 3889 | /* |
| 3890 | * Before anything else, update keys in the parent and other ancestors |
| 3891 | * if needed, then release the write locks on them, so that other tasks |
| 3892 | * can use them while we modify the leaf. |
| 3893 | */ |
| 3894 | if (path->slots[0] == 0) { |
| 3895 | btrfs_cpu_key_to_disk(&disk_key, &batch->keys[0]); |
| 3896 | fixup_low_keys(path, &disk_key, 1); |
| 3897 | } |
| 3898 | btrfs_unlock_up_safe(path, 1); |
| 3899 | |
| 3900 | leaf = path->nodes[0]; |
| 3901 | slot = path->slots[0]; |
| 3902 | |
| 3903 | nritems = btrfs_header_nritems(leaf); |
| 3904 | data_end = leaf_data_end(leaf); |
| 3905 | total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item)); |
| 3906 | |
| 3907 | if (btrfs_leaf_free_space(leaf) < total_size) { |
| 3908 | btrfs_print_leaf(leaf); |
| 3909 | btrfs_crit(fs_info, "not enough freespace need %u have %d", |
| 3910 | total_size, btrfs_leaf_free_space(leaf)); |
| 3911 | BUG(); |
| 3912 | } |
| 3913 | |
| 3914 | btrfs_init_map_token(&token, leaf); |
| 3915 | if (slot != nritems) { |
| 3916 | unsigned int old_data = btrfs_item_data_end(leaf, slot); |
| 3917 | |
| 3918 | if (old_data < data_end) { |
| 3919 | btrfs_print_leaf(leaf); |
| 3920 | btrfs_crit(fs_info, |
| 3921 | "item at slot %d with data offset %u beyond data end of leaf %u", |
| 3922 | slot, old_data, data_end); |
| 3923 | BUG(); |
| 3924 | } |
| 3925 | /* |
| 3926 | * item0..itemN ... dataN.offset..dataN.size .. data0.size |
| 3927 | */ |
| 3928 | /* first correct the data pointers */ |
| 3929 | for (i = slot; i < nritems; i++) { |
| 3930 | u32 ioff; |
| 3931 | |
| 3932 | ioff = btrfs_token_item_offset(&token, i); |
| 3933 | btrfs_set_token_item_offset(&token, i, |
| 3934 | ioff - batch->total_data_size); |
| 3935 | } |
| 3936 | /* shift the items */ |
| 3937 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + batch->nr), |
| 3938 | btrfs_item_nr_offset(slot), |
| 3939 | (nritems - slot) * sizeof(struct btrfs_item)); |
| 3940 | |
| 3941 | /* shift the data */ |
| 3942 | memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
| 3943 | data_end - batch->total_data_size, |
| 3944 | BTRFS_LEAF_DATA_OFFSET + data_end, |
| 3945 | old_data - data_end); |
| 3946 | data_end = old_data; |
| 3947 | } |
| 3948 | |
| 3949 | /* setup the item for the new data */ |
| 3950 | for (i = 0; i < batch->nr; i++) { |
| 3951 | btrfs_cpu_key_to_disk(&disk_key, &batch->keys[i]); |
| 3952 | btrfs_set_item_key(leaf, &disk_key, slot + i); |
| 3953 | data_end -= batch->data_sizes[i]; |
| 3954 | btrfs_set_token_item_offset(&token, slot + i, data_end); |
| 3955 | btrfs_set_token_item_size(&token, slot + i, batch->data_sizes[i]); |
| 3956 | } |
| 3957 | |
| 3958 | btrfs_set_header_nritems(leaf, nritems + batch->nr); |
| 3959 | btrfs_mark_buffer_dirty(leaf); |
| 3960 | |
| 3961 | if (btrfs_leaf_free_space(leaf) < 0) { |
| 3962 | btrfs_print_leaf(leaf); |
| 3963 | BUG(); |
| 3964 | } |
| 3965 | } |
| 3966 | |
| 3967 | /* |
| 3968 | * Insert a new item into a leaf. |
| 3969 | * |
| 3970 | * @root: The root of the btree. |
| 3971 | * @path: A path pointing to the target leaf and slot. |
| 3972 | * @key: The key of the new item. |
| 3973 | * @data_size: The size of the data associated with the new key. |
| 3974 | */ |
| 3975 | void btrfs_setup_item_for_insert(struct btrfs_root *root, |
| 3976 | struct btrfs_path *path, |
| 3977 | const struct btrfs_key *key, |
| 3978 | u32 data_size) |
| 3979 | { |
| 3980 | struct btrfs_item_batch batch; |
| 3981 | |
| 3982 | batch.keys = key; |
| 3983 | batch.data_sizes = &data_size; |
| 3984 | batch.total_data_size = data_size; |
| 3985 | batch.nr = 1; |
| 3986 | |
| 3987 | setup_items_for_insert(root, path, &batch); |
| 3988 | } |
| 3989 | |
| 3990 | /* |
| 3991 | * Given a key and some data, insert items into the tree. |
| 3992 | * This does all the path init required, making room in the tree if needed. |
| 3993 | */ |
| 3994 | int btrfs_insert_empty_items(struct btrfs_trans_handle *trans, |
| 3995 | struct btrfs_root *root, |
| 3996 | struct btrfs_path *path, |
| 3997 | const struct btrfs_item_batch *batch) |
| 3998 | { |
| 3999 | int ret = 0; |
| 4000 | int slot; |
| 4001 | u32 total_size; |
| 4002 | |
| 4003 | total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item)); |
| 4004 | ret = btrfs_search_slot(trans, root, &batch->keys[0], path, total_size, 1); |
| 4005 | if (ret == 0) |
| 4006 | return -EEXIST; |
| 4007 | if (ret < 0) |
| 4008 | return ret; |
| 4009 | |
| 4010 | slot = path->slots[0]; |
| 4011 | BUG_ON(slot < 0); |
| 4012 | |
| 4013 | setup_items_for_insert(root, path, batch); |
| 4014 | return 0; |
| 4015 | } |
| 4016 | |
| 4017 | /* |
| 4018 | * Given a key and some data, insert an item into the tree. |
| 4019 | * This does all the path init required, making room in the tree if needed. |
| 4020 | */ |
| 4021 | int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 4022 | const struct btrfs_key *cpu_key, void *data, |
| 4023 | u32 data_size) |
| 4024 | { |
| 4025 | int ret = 0; |
| 4026 | struct btrfs_path *path; |
| 4027 | struct extent_buffer *leaf; |
| 4028 | unsigned long ptr; |
| 4029 | |
| 4030 | path = btrfs_alloc_path(); |
| 4031 | if (!path) |
| 4032 | return -ENOMEM; |
| 4033 | ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); |
| 4034 | if (!ret) { |
| 4035 | leaf = path->nodes[0]; |
| 4036 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
| 4037 | write_extent_buffer(leaf, data, ptr, data_size); |
| 4038 | btrfs_mark_buffer_dirty(leaf); |
| 4039 | } |
| 4040 | btrfs_free_path(path); |
| 4041 | return ret; |
| 4042 | } |
| 4043 | |
| 4044 | /* |
| 4045 | * This function duplicates an item, giving 'new_key' to the new item. |
| 4046 | * It guarantees both items live in the same tree leaf and the new item is |
| 4047 | * contiguous with the original item. |
| 4048 | * |
| 4049 | * This allows us to split a file extent in place, keeping a lock on the leaf |
| 4050 | * the entire time. |
| 4051 | */ |
| 4052 | int btrfs_duplicate_item(struct btrfs_trans_handle *trans, |
| 4053 | struct btrfs_root *root, |
| 4054 | struct btrfs_path *path, |
| 4055 | const struct btrfs_key *new_key) |
| 4056 | { |
| 4057 | struct extent_buffer *leaf; |
| 4058 | int ret; |
| 4059 | u32 item_size; |
| 4060 | |
| 4061 | leaf = path->nodes[0]; |
| 4062 | item_size = btrfs_item_size(leaf, path->slots[0]); |
| 4063 | ret = setup_leaf_for_split(trans, root, path, |
| 4064 | item_size + sizeof(struct btrfs_item)); |
| 4065 | if (ret) |
| 4066 | return ret; |
| 4067 | |
| 4068 | path->slots[0]++; |
| 4069 | btrfs_setup_item_for_insert(root, path, new_key, item_size); |
| 4070 | leaf = path->nodes[0]; |
| 4071 | memcpy_extent_buffer(leaf, |
| 4072 | btrfs_item_ptr_offset(leaf, path->slots[0]), |
| 4073 | btrfs_item_ptr_offset(leaf, path->slots[0] - 1), |
| 4074 | item_size); |
| 4075 | return 0; |
| 4076 | } |
| 4077 | |
| 4078 | /* |
| 4079 | * delete the pointer from a given node. |
| 4080 | * |
| 4081 | * the tree should have been previously balanced so the deletion does not |
| 4082 | * empty a node. |
| 4083 | */ |
| 4084 | static void del_ptr(struct btrfs_root *root, struct btrfs_path *path, |
| 4085 | int level, int slot) |
| 4086 | { |
| 4087 | struct extent_buffer *parent = path->nodes[level]; |
| 4088 | u32 nritems; |
| 4089 | int ret; |
| 4090 | |
| 4091 | nritems = btrfs_header_nritems(parent); |
| 4092 | if (slot != nritems - 1) { |
| 4093 | if (level) { |
| 4094 | ret = btrfs_tree_mod_log_insert_move(parent, slot, |
| 4095 | slot + 1, nritems - slot - 1); |
| 4096 | BUG_ON(ret < 0); |
| 4097 | } |
| 4098 | memmove_extent_buffer(parent, |
| 4099 | btrfs_node_key_ptr_offset(slot), |
| 4100 | btrfs_node_key_ptr_offset(slot + 1), |
| 4101 | sizeof(struct btrfs_key_ptr) * |
| 4102 | (nritems - slot - 1)); |
| 4103 | } else if (level) { |
| 4104 | ret = btrfs_tree_mod_log_insert_key(parent, slot, |
| 4105 | BTRFS_MOD_LOG_KEY_REMOVE, GFP_NOFS); |
| 4106 | BUG_ON(ret < 0); |
| 4107 | } |
| 4108 | |
| 4109 | nritems--; |
| 4110 | btrfs_set_header_nritems(parent, nritems); |
| 4111 | if (nritems == 0 && parent == root->node) { |
| 4112 | BUG_ON(btrfs_header_level(root->node) != 1); |
| 4113 | /* just turn the root into a leaf and break */ |
| 4114 | btrfs_set_header_level(root->node, 0); |
| 4115 | } else if (slot == 0) { |
| 4116 | struct btrfs_disk_key disk_key; |
| 4117 | |
| 4118 | btrfs_node_key(parent, &disk_key, 0); |
| 4119 | fixup_low_keys(path, &disk_key, level + 1); |
| 4120 | } |
| 4121 | btrfs_mark_buffer_dirty(parent); |
| 4122 | } |
| 4123 | |
| 4124 | /* |
| 4125 | * a helper function to delete the leaf pointed to by path->slots[1] and |
| 4126 | * path->nodes[1]. |
| 4127 | * |
| 4128 | * This deletes the pointer in path->nodes[1] and frees the leaf |
| 4129 | * block extent. zero is returned if it all worked out, < 0 otherwise. |
| 4130 | * |
| 4131 | * The path must have already been setup for deleting the leaf, including |
| 4132 | * all the proper balancing. path->nodes[1] must be locked. |
| 4133 | */ |
| 4134 | static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans, |
| 4135 | struct btrfs_root *root, |
| 4136 | struct btrfs_path *path, |
| 4137 | struct extent_buffer *leaf) |
| 4138 | { |
| 4139 | WARN_ON(btrfs_header_generation(leaf) != trans->transid); |
| 4140 | del_ptr(root, path, 1, path->slots[1]); |
| 4141 | |
| 4142 | /* |
| 4143 | * btrfs_free_extent is expensive, we want to make sure we |
| 4144 | * aren't holding any locks when we call it |
| 4145 | */ |
| 4146 | btrfs_unlock_up_safe(path, 0); |
| 4147 | |
| 4148 | root_sub_used(root, leaf->len); |
| 4149 | |
| 4150 | atomic_inc(&leaf->refs); |
| 4151 | btrfs_free_tree_block(trans, btrfs_root_id(root), leaf, 0, 1); |
| 4152 | free_extent_buffer_stale(leaf); |
| 4153 | } |
| 4154 | /* |
| 4155 | * delete the item at the leaf level in path. If that empties |
| 4156 | * the leaf, remove it from the tree |
| 4157 | */ |
| 4158 | int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| 4159 | struct btrfs_path *path, int slot, int nr) |
| 4160 | { |
| 4161 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 4162 | struct extent_buffer *leaf; |
| 4163 | int ret = 0; |
| 4164 | int wret; |
| 4165 | u32 nritems; |
| 4166 | |
| 4167 | leaf = path->nodes[0]; |
| 4168 | nritems = btrfs_header_nritems(leaf); |
| 4169 | |
| 4170 | if (slot + nr != nritems) { |
| 4171 | const u32 last_off = btrfs_item_offset(leaf, slot + nr - 1); |
| 4172 | const int data_end = leaf_data_end(leaf); |
| 4173 | struct btrfs_map_token token; |
| 4174 | u32 dsize = 0; |
| 4175 | int i; |
| 4176 | |
| 4177 | for (i = 0; i < nr; i++) |
| 4178 | dsize += btrfs_item_size(leaf, slot + i); |
| 4179 | |
| 4180 | memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
| 4181 | data_end + dsize, |
| 4182 | BTRFS_LEAF_DATA_OFFSET + data_end, |
| 4183 | last_off - data_end); |
| 4184 | |
| 4185 | btrfs_init_map_token(&token, leaf); |
| 4186 | for (i = slot + nr; i < nritems; i++) { |
| 4187 | u32 ioff; |
| 4188 | |
| 4189 | ioff = btrfs_token_item_offset(&token, i); |
| 4190 | btrfs_set_token_item_offset(&token, i, ioff + dsize); |
| 4191 | } |
| 4192 | |
| 4193 | memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot), |
| 4194 | btrfs_item_nr_offset(slot + nr), |
| 4195 | sizeof(struct btrfs_item) * |
| 4196 | (nritems - slot - nr)); |
| 4197 | } |
| 4198 | btrfs_set_header_nritems(leaf, nritems - nr); |
| 4199 | nritems -= nr; |
| 4200 | |
| 4201 | /* delete the leaf if we've emptied it */ |
| 4202 | if (nritems == 0) { |
| 4203 | if (leaf == root->node) { |
| 4204 | btrfs_set_header_level(leaf, 0); |
| 4205 | } else { |
| 4206 | btrfs_clean_tree_block(leaf); |
| 4207 | btrfs_del_leaf(trans, root, path, leaf); |
| 4208 | } |
| 4209 | } else { |
| 4210 | int used = leaf_space_used(leaf, 0, nritems); |
| 4211 | if (slot == 0) { |
| 4212 | struct btrfs_disk_key disk_key; |
| 4213 | |
| 4214 | btrfs_item_key(leaf, &disk_key, 0); |
| 4215 | fixup_low_keys(path, &disk_key, 1); |
| 4216 | } |
| 4217 | |
| 4218 | /* |
| 4219 | * Try to delete the leaf if it is mostly empty. We do this by |
| 4220 | * trying to move all its items into its left and right neighbours. |
| 4221 | * If we can't move all the items, then we don't delete it - it's |
| 4222 | * not ideal, but future insertions might fill the leaf with more |
| 4223 | * items, or items from other leaves might be moved later into our |
| 4224 | * leaf due to deletions on those leaves. |
| 4225 | */ |
| 4226 | if (used < BTRFS_LEAF_DATA_SIZE(fs_info) / 3) { |
| 4227 | u32 min_push_space; |
| 4228 | |
| 4229 | /* push_leaf_left fixes the path. |
| 4230 | * make sure the path still points to our leaf |
| 4231 | * for possible call to del_ptr below |
| 4232 | */ |
| 4233 | slot = path->slots[1]; |
| 4234 | atomic_inc(&leaf->refs); |
| 4235 | /* |
| 4236 | * We want to be able to at least push one item to the |
| 4237 | * left neighbour leaf, and that's the first item. |
| 4238 | */ |
| 4239 | min_push_space = sizeof(struct btrfs_item) + |
| 4240 | btrfs_item_size(leaf, 0); |
| 4241 | wret = push_leaf_left(trans, root, path, 0, |
| 4242 | min_push_space, 1, (u32)-1); |
| 4243 | if (wret < 0 && wret != -ENOSPC) |
| 4244 | ret = wret; |
| 4245 | |
| 4246 | if (path->nodes[0] == leaf && |
| 4247 | btrfs_header_nritems(leaf)) { |
| 4248 | /* |
| 4249 | * If we were not able to push all items from our |
| 4250 | * leaf to its left neighbour, then attempt to |
| 4251 | * either push all the remaining items to the |
| 4252 | * right neighbour or none. There's no advantage |
| 4253 | * in pushing only some items, instead of all, as |
| 4254 | * it's pointless to end up with a leaf having |
| 4255 | * too few items while the neighbours can be full |
| 4256 | * or nearly full. |
| 4257 | */ |
| 4258 | nritems = btrfs_header_nritems(leaf); |
| 4259 | min_push_space = leaf_space_used(leaf, 0, nritems); |
| 4260 | wret = push_leaf_right(trans, root, path, 0, |
| 4261 | min_push_space, 1, 0); |
| 4262 | if (wret < 0 && wret != -ENOSPC) |
| 4263 | ret = wret; |
| 4264 | } |
| 4265 | |
| 4266 | if (btrfs_header_nritems(leaf) == 0) { |
| 4267 | path->slots[1] = slot; |
| 4268 | btrfs_del_leaf(trans, root, path, leaf); |
| 4269 | free_extent_buffer(leaf); |
| 4270 | ret = 0; |
| 4271 | } else { |
| 4272 | /* if we're still in the path, make sure |
| 4273 | * we're dirty. Otherwise, one of the |
| 4274 | * push_leaf functions must have already |
| 4275 | * dirtied this buffer |
| 4276 | */ |
| 4277 | if (path->nodes[0] == leaf) |
| 4278 | btrfs_mark_buffer_dirty(leaf); |
| 4279 | free_extent_buffer(leaf); |
| 4280 | } |
| 4281 | } else { |
| 4282 | btrfs_mark_buffer_dirty(leaf); |
| 4283 | } |
| 4284 | } |
| 4285 | return ret; |
| 4286 | } |
| 4287 | |
| 4288 | /* |
| 4289 | * search the tree again to find a leaf with lesser keys |
| 4290 | * returns 0 if it found something or 1 if there are no lesser leaves. |
| 4291 | * returns < 0 on io errors. |
| 4292 | * |
| 4293 | * This may release the path, and so you may lose any locks held at the |
| 4294 | * time you call it. |
| 4295 | */ |
| 4296 | int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) |
| 4297 | { |
| 4298 | struct btrfs_key key; |
| 4299 | struct btrfs_disk_key found_key; |
| 4300 | int ret; |
| 4301 | |
| 4302 | btrfs_item_key_to_cpu(path->nodes[0], &key, 0); |
| 4303 | |
| 4304 | if (key.offset > 0) { |
| 4305 | key.offset--; |
| 4306 | } else if (key.type > 0) { |
| 4307 | key.type--; |
| 4308 | key.offset = (u64)-1; |
| 4309 | } else if (key.objectid > 0) { |
| 4310 | key.objectid--; |
| 4311 | key.type = (u8)-1; |
| 4312 | key.offset = (u64)-1; |
| 4313 | } else { |
| 4314 | return 1; |
| 4315 | } |
| 4316 | |
| 4317 | btrfs_release_path(path); |
| 4318 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
| 4319 | if (ret < 0) |
| 4320 | return ret; |
| 4321 | btrfs_item_key(path->nodes[0], &found_key, 0); |
| 4322 | ret = comp_keys(&found_key, &key); |
| 4323 | /* |
| 4324 | * We might have had an item with the previous key in the tree right |
| 4325 | * before we released our path. And after we released our path, that |
| 4326 | * item might have been pushed to the first slot (0) of the leaf we |
| 4327 | * were holding due to a tree balance. Alternatively, an item with the |
| 4328 | * previous key can exist as the only element of a leaf (big fat item). |
| 4329 | * Therefore account for these 2 cases, so that our callers (like |
| 4330 | * btrfs_previous_item) don't miss an existing item with a key matching |
| 4331 | * the previous key we computed above. |
| 4332 | */ |
| 4333 | if (ret <= 0) |
| 4334 | return 0; |
| 4335 | return 1; |
| 4336 | } |
| 4337 | |
| 4338 | /* |
| 4339 | * A helper function to walk down the tree starting at min_key, and looking |
| 4340 | * for nodes or leaves that are have a minimum transaction id. |
| 4341 | * This is used by the btree defrag code, and tree logging |
| 4342 | * |
| 4343 | * This does not cow, but it does stuff the starting key it finds back |
| 4344 | * into min_key, so you can call btrfs_search_slot with cow=1 on the |
| 4345 | * key and get a writable path. |
| 4346 | * |
| 4347 | * This honors path->lowest_level to prevent descent past a given level |
| 4348 | * of the tree. |
| 4349 | * |
| 4350 | * min_trans indicates the oldest transaction that you are interested |
| 4351 | * in walking through. Any nodes or leaves older than min_trans are |
| 4352 | * skipped over (without reading them). |
| 4353 | * |
| 4354 | * returns zero if something useful was found, < 0 on error and 1 if there |
| 4355 | * was nothing in the tree that matched the search criteria. |
| 4356 | */ |
| 4357 | int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, |
| 4358 | struct btrfs_path *path, |
| 4359 | u64 min_trans) |
| 4360 | { |
| 4361 | struct extent_buffer *cur; |
| 4362 | struct btrfs_key found_key; |
| 4363 | int slot; |
| 4364 | int sret; |
| 4365 | u32 nritems; |
| 4366 | int level; |
| 4367 | int ret = 1; |
| 4368 | int keep_locks = path->keep_locks; |
| 4369 | |
| 4370 | path->keep_locks = 1; |
| 4371 | again: |
| 4372 | cur = btrfs_read_lock_root_node(root); |
| 4373 | level = btrfs_header_level(cur); |
| 4374 | WARN_ON(path->nodes[level]); |
| 4375 | path->nodes[level] = cur; |
| 4376 | path->locks[level] = BTRFS_READ_LOCK; |
| 4377 | |
| 4378 | if (btrfs_header_generation(cur) < min_trans) { |
| 4379 | ret = 1; |
| 4380 | goto out; |
| 4381 | } |
| 4382 | while (1) { |
| 4383 | nritems = btrfs_header_nritems(cur); |
| 4384 | level = btrfs_header_level(cur); |
| 4385 | sret = btrfs_bin_search(cur, min_key, &slot); |
| 4386 | if (sret < 0) { |
| 4387 | ret = sret; |
| 4388 | goto out; |
| 4389 | } |
| 4390 | |
| 4391 | /* at the lowest level, we're done, setup the path and exit */ |
| 4392 | if (level == path->lowest_level) { |
| 4393 | if (slot >= nritems) |
| 4394 | goto find_next_key; |
| 4395 | ret = 0; |
| 4396 | path->slots[level] = slot; |
| 4397 | btrfs_item_key_to_cpu(cur, &found_key, slot); |
| 4398 | goto out; |
| 4399 | } |
| 4400 | if (sret && slot > 0) |
| 4401 | slot--; |
| 4402 | /* |
| 4403 | * check this node pointer against the min_trans parameters. |
| 4404 | * If it is too old, skip to the next one. |
| 4405 | */ |
| 4406 | while (slot < nritems) { |
| 4407 | u64 gen; |
| 4408 | |
| 4409 | gen = btrfs_node_ptr_generation(cur, slot); |
| 4410 | if (gen < min_trans) { |
| 4411 | slot++; |
| 4412 | continue; |
| 4413 | } |
| 4414 | break; |
| 4415 | } |
| 4416 | find_next_key: |
| 4417 | /* |
| 4418 | * we didn't find a candidate key in this node, walk forward |
| 4419 | * and find another one |
| 4420 | */ |
| 4421 | if (slot >= nritems) { |
| 4422 | path->slots[level] = slot; |
| 4423 | sret = btrfs_find_next_key(root, path, min_key, level, |
| 4424 | min_trans); |
| 4425 | if (sret == 0) { |
| 4426 | btrfs_release_path(path); |
| 4427 | goto again; |
| 4428 | } else { |
| 4429 | goto out; |
| 4430 | } |
| 4431 | } |
| 4432 | /* save our key for returning back */ |
| 4433 | btrfs_node_key_to_cpu(cur, &found_key, slot); |
| 4434 | path->slots[level] = slot; |
| 4435 | if (level == path->lowest_level) { |
| 4436 | ret = 0; |
| 4437 | goto out; |
| 4438 | } |
| 4439 | cur = btrfs_read_node_slot(cur, slot); |
| 4440 | if (IS_ERR(cur)) { |
| 4441 | ret = PTR_ERR(cur); |
| 4442 | goto out; |
| 4443 | } |
| 4444 | |
| 4445 | btrfs_tree_read_lock(cur); |
| 4446 | |
| 4447 | path->locks[level - 1] = BTRFS_READ_LOCK; |
| 4448 | path->nodes[level - 1] = cur; |
| 4449 | unlock_up(path, level, 1, 0, NULL); |
| 4450 | } |
| 4451 | out: |
| 4452 | path->keep_locks = keep_locks; |
| 4453 | if (ret == 0) { |
| 4454 | btrfs_unlock_up_safe(path, path->lowest_level + 1); |
| 4455 | memcpy(min_key, &found_key, sizeof(found_key)); |
| 4456 | } |
| 4457 | return ret; |
| 4458 | } |
| 4459 | |
| 4460 | /* |
| 4461 | * this is similar to btrfs_next_leaf, but does not try to preserve |
| 4462 | * and fixup the path. It looks for and returns the next key in the |
| 4463 | * tree based on the current path and the min_trans parameters. |
| 4464 | * |
| 4465 | * 0 is returned if another key is found, < 0 if there are any errors |
| 4466 | * and 1 is returned if there are no higher keys in the tree |
| 4467 | * |
| 4468 | * path->keep_locks should be set to 1 on the search made before |
| 4469 | * calling this function. |
| 4470 | */ |
| 4471 | int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path, |
| 4472 | struct btrfs_key *key, int level, u64 min_trans) |
| 4473 | { |
| 4474 | int slot; |
| 4475 | struct extent_buffer *c; |
| 4476 | |
| 4477 | WARN_ON(!path->keep_locks && !path->skip_locking); |
| 4478 | while (level < BTRFS_MAX_LEVEL) { |
| 4479 | if (!path->nodes[level]) |
| 4480 | return 1; |
| 4481 | |
| 4482 | slot = path->slots[level] + 1; |
| 4483 | c = path->nodes[level]; |
| 4484 | next: |
| 4485 | if (slot >= btrfs_header_nritems(c)) { |
| 4486 | int ret; |
| 4487 | int orig_lowest; |
| 4488 | struct btrfs_key cur_key; |
| 4489 | if (level + 1 >= BTRFS_MAX_LEVEL || |
| 4490 | !path->nodes[level + 1]) |
| 4491 | return 1; |
| 4492 | |
| 4493 | if (path->locks[level + 1] || path->skip_locking) { |
| 4494 | level++; |
| 4495 | continue; |
| 4496 | } |
| 4497 | |
| 4498 | slot = btrfs_header_nritems(c) - 1; |
| 4499 | if (level == 0) |
| 4500 | btrfs_item_key_to_cpu(c, &cur_key, slot); |
| 4501 | else |
| 4502 | btrfs_node_key_to_cpu(c, &cur_key, slot); |
| 4503 | |
| 4504 | orig_lowest = path->lowest_level; |
| 4505 | btrfs_release_path(path); |
| 4506 | path->lowest_level = level; |
| 4507 | ret = btrfs_search_slot(NULL, root, &cur_key, path, |
| 4508 | 0, 0); |
| 4509 | path->lowest_level = orig_lowest; |
| 4510 | if (ret < 0) |
| 4511 | return ret; |
| 4512 | |
| 4513 | c = path->nodes[level]; |
| 4514 | slot = path->slots[level]; |
| 4515 | if (ret == 0) |
| 4516 | slot++; |
| 4517 | goto next; |
| 4518 | } |
| 4519 | |
| 4520 | if (level == 0) |
| 4521 | btrfs_item_key_to_cpu(c, key, slot); |
| 4522 | else { |
| 4523 | u64 gen = btrfs_node_ptr_generation(c, slot); |
| 4524 | |
| 4525 | if (gen < min_trans) { |
| 4526 | slot++; |
| 4527 | goto next; |
| 4528 | } |
| 4529 | btrfs_node_key_to_cpu(c, key, slot); |
| 4530 | } |
| 4531 | return 0; |
| 4532 | } |
| 4533 | return 1; |
| 4534 | } |
| 4535 | |
| 4536 | int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, |
| 4537 | u64 time_seq) |
| 4538 | { |
| 4539 | int slot; |
| 4540 | int level; |
| 4541 | struct extent_buffer *c; |
| 4542 | struct extent_buffer *next; |
| 4543 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 4544 | struct btrfs_key key; |
| 4545 | bool need_commit_sem = false; |
| 4546 | u32 nritems; |
| 4547 | int ret; |
| 4548 | int i; |
| 4549 | |
| 4550 | nritems = btrfs_header_nritems(path->nodes[0]); |
| 4551 | if (nritems == 0) |
| 4552 | return 1; |
| 4553 | |
| 4554 | btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1); |
| 4555 | again: |
| 4556 | level = 1; |
| 4557 | next = NULL; |
| 4558 | btrfs_release_path(path); |
| 4559 | |
| 4560 | path->keep_locks = 1; |
| 4561 | |
| 4562 | if (time_seq) { |
| 4563 | ret = btrfs_search_old_slot(root, &key, path, time_seq); |
| 4564 | } else { |
| 4565 | if (path->need_commit_sem) { |
| 4566 | path->need_commit_sem = 0; |
| 4567 | need_commit_sem = true; |
| 4568 | down_read(&fs_info->commit_root_sem); |
| 4569 | } |
| 4570 | ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
| 4571 | } |
| 4572 | path->keep_locks = 0; |
| 4573 | |
| 4574 | if (ret < 0) |
| 4575 | goto done; |
| 4576 | |
| 4577 | nritems = btrfs_header_nritems(path->nodes[0]); |
| 4578 | /* |
| 4579 | * by releasing the path above we dropped all our locks. A balance |
| 4580 | * could have added more items next to the key that used to be |
| 4581 | * at the very end of the block. So, check again here and |
| 4582 | * advance the path if there are now more items available. |
| 4583 | */ |
| 4584 | if (nritems > 0 && path->slots[0] < nritems - 1) { |
| 4585 | if (ret == 0) |
| 4586 | path->slots[0]++; |
| 4587 | ret = 0; |
| 4588 | goto done; |
| 4589 | } |
| 4590 | /* |
| 4591 | * So the above check misses one case: |
| 4592 | * - after releasing the path above, someone has removed the item that |
| 4593 | * used to be at the very end of the block, and balance between leafs |
| 4594 | * gets another one with bigger key.offset to replace it. |
| 4595 | * |
| 4596 | * This one should be returned as well, or we can get leaf corruption |
| 4597 | * later(esp. in __btrfs_drop_extents()). |
| 4598 | * |
| 4599 | * And a bit more explanation about this check, |
| 4600 | * with ret > 0, the key isn't found, the path points to the slot |
| 4601 | * where it should be inserted, so the path->slots[0] item must be the |
| 4602 | * bigger one. |
| 4603 | */ |
| 4604 | if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) { |
| 4605 | ret = 0; |
| 4606 | goto done; |
| 4607 | } |
| 4608 | |
| 4609 | while (level < BTRFS_MAX_LEVEL) { |
| 4610 | if (!path->nodes[level]) { |
| 4611 | ret = 1; |
| 4612 | goto done; |
| 4613 | } |
| 4614 | |
| 4615 | slot = path->slots[level] + 1; |
| 4616 | c = path->nodes[level]; |
| 4617 | if (slot >= btrfs_header_nritems(c)) { |
| 4618 | level++; |
| 4619 | if (level == BTRFS_MAX_LEVEL) { |
| 4620 | ret = 1; |
| 4621 | goto done; |
| 4622 | } |
| 4623 | continue; |
| 4624 | } |
| 4625 | |
| 4626 | |
| 4627 | /* |
| 4628 | * Our current level is where we're going to start from, and to |
| 4629 | * make sure lockdep doesn't complain we need to drop our locks |
| 4630 | * and nodes from 0 to our current level. |
| 4631 | */ |
| 4632 | for (i = 0; i < level; i++) { |
| 4633 | if (path->locks[level]) { |
| 4634 | btrfs_tree_read_unlock(path->nodes[i]); |
| 4635 | path->locks[i] = 0; |
| 4636 | } |
| 4637 | free_extent_buffer(path->nodes[i]); |
| 4638 | path->nodes[i] = NULL; |
| 4639 | } |
| 4640 | |
| 4641 | next = c; |
| 4642 | ret = read_block_for_search(root, path, &next, level, |
| 4643 | slot, &key); |
| 4644 | if (ret == -EAGAIN) |
| 4645 | goto again; |
| 4646 | |
| 4647 | if (ret < 0) { |
| 4648 | btrfs_release_path(path); |
| 4649 | goto done; |
| 4650 | } |
| 4651 | |
| 4652 | if (!path->skip_locking) { |
| 4653 | ret = btrfs_try_tree_read_lock(next); |
| 4654 | if (!ret && time_seq) { |
| 4655 | /* |
| 4656 | * If we don't get the lock, we may be racing |
| 4657 | * with push_leaf_left, holding that lock while |
| 4658 | * itself waiting for the leaf we've currently |
| 4659 | * locked. To solve this situation, we give up |
| 4660 | * on our lock and cycle. |
| 4661 | */ |
| 4662 | free_extent_buffer(next); |
| 4663 | btrfs_release_path(path); |
| 4664 | cond_resched(); |
| 4665 | goto again; |
| 4666 | } |
| 4667 | if (!ret) |
| 4668 | btrfs_tree_read_lock(next); |
| 4669 | } |
| 4670 | break; |
| 4671 | } |
| 4672 | path->slots[level] = slot; |
| 4673 | while (1) { |
| 4674 | level--; |
| 4675 | path->nodes[level] = next; |
| 4676 | path->slots[level] = 0; |
| 4677 | if (!path->skip_locking) |
| 4678 | path->locks[level] = BTRFS_READ_LOCK; |
| 4679 | if (!level) |
| 4680 | break; |
| 4681 | |
| 4682 | ret = read_block_for_search(root, path, &next, level, |
| 4683 | 0, &key); |
| 4684 | if (ret == -EAGAIN) |
| 4685 | goto again; |
| 4686 | |
| 4687 | if (ret < 0) { |
| 4688 | btrfs_release_path(path); |
| 4689 | goto done; |
| 4690 | } |
| 4691 | |
| 4692 | if (!path->skip_locking) |
| 4693 | btrfs_tree_read_lock(next); |
| 4694 | } |
| 4695 | ret = 0; |
| 4696 | done: |
| 4697 | unlock_up(path, 0, 1, 0, NULL); |
| 4698 | if (need_commit_sem) { |
| 4699 | int ret2; |
| 4700 | |
| 4701 | path->need_commit_sem = 1; |
| 4702 | ret2 = finish_need_commit_sem_search(path); |
| 4703 | up_read(&fs_info->commit_root_sem); |
| 4704 | if (ret2) |
| 4705 | ret = ret2; |
| 4706 | } |
| 4707 | |
| 4708 | return ret; |
| 4709 | } |
| 4710 | |
| 4711 | /* |
| 4712 | * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps |
| 4713 | * searching until it gets past min_objectid or finds an item of 'type' |
| 4714 | * |
| 4715 | * returns 0 if something is found, 1 if nothing was found and < 0 on error |
| 4716 | */ |
| 4717 | int btrfs_previous_item(struct btrfs_root *root, |
| 4718 | struct btrfs_path *path, u64 min_objectid, |
| 4719 | int type) |
| 4720 | { |
| 4721 | struct btrfs_key found_key; |
| 4722 | struct extent_buffer *leaf; |
| 4723 | u32 nritems; |
| 4724 | int ret; |
| 4725 | |
| 4726 | while (1) { |
| 4727 | if (path->slots[0] == 0) { |
| 4728 | ret = btrfs_prev_leaf(root, path); |
| 4729 | if (ret != 0) |
| 4730 | return ret; |
| 4731 | } else { |
| 4732 | path->slots[0]--; |
| 4733 | } |
| 4734 | leaf = path->nodes[0]; |
| 4735 | nritems = btrfs_header_nritems(leaf); |
| 4736 | if (nritems == 0) |
| 4737 | return 1; |
| 4738 | if (path->slots[0] == nritems) |
| 4739 | path->slots[0]--; |
| 4740 | |
| 4741 | btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); |
| 4742 | if (found_key.objectid < min_objectid) |
| 4743 | break; |
| 4744 | if (found_key.type == type) |
| 4745 | return 0; |
| 4746 | if (found_key.objectid == min_objectid && |
| 4747 | found_key.type < type) |
| 4748 | break; |
| 4749 | } |
| 4750 | return 1; |
| 4751 | } |
| 4752 | |
| 4753 | /* |
| 4754 | * search in extent tree to find a previous Metadata/Data extent item with |
| 4755 | * min objecitd. |
| 4756 | * |
| 4757 | * returns 0 if something is found, 1 if nothing was found and < 0 on error |
| 4758 | */ |
| 4759 | int btrfs_previous_extent_item(struct btrfs_root *root, |
| 4760 | struct btrfs_path *path, u64 min_objectid) |
| 4761 | { |
| 4762 | struct btrfs_key found_key; |
| 4763 | struct extent_buffer *leaf; |
| 4764 | u32 nritems; |
| 4765 | int ret; |
| 4766 | |
| 4767 | while (1) { |
| 4768 | if (path->slots[0] == 0) { |
| 4769 | ret = btrfs_prev_leaf(root, path); |
| 4770 | if (ret != 0) |
| 4771 | return ret; |
| 4772 | } else { |
| 4773 | path->slots[0]--; |
| 4774 | } |
| 4775 | leaf = path->nodes[0]; |
| 4776 | nritems = btrfs_header_nritems(leaf); |
| 4777 | if (nritems == 0) |
| 4778 | return 1; |
| 4779 | if (path->slots[0] == nritems) |
| 4780 | path->slots[0]--; |
| 4781 | |
| 4782 | btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); |
| 4783 | if (found_key.objectid < min_objectid) |
| 4784 | break; |
| 4785 | if (found_key.type == BTRFS_EXTENT_ITEM_KEY || |
| 4786 | found_key.type == BTRFS_METADATA_ITEM_KEY) |
| 4787 | return 0; |
| 4788 | if (found_key.objectid == min_objectid && |
| 4789 | found_key.type < BTRFS_EXTENT_ITEM_KEY) |
| 4790 | break; |
| 4791 | } |
| 4792 | return 1; |
| 4793 | } |