1/*
   2 * Copyright (C) 2007 Oracle.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#include <linux/fs.h>
  20#include <linux/slab.h>
  21#include <linux/sched.h>
  22#include <linux/writeback.h>
  23#include <linux/pagemap.h>
  24#include <linux/blkdev.h>
  25#include <linux/uuid.h>
  26#include "ctree.h"
  27#include "disk-io.h"
  28#include "transaction.h"
  29#include "locking.h"
  30#include "tree-log.h"
  31#include "inode-map.h"
  32#include "volumes.h"
  33#include "dev-replace.h"
 
  34
  35#define BTRFS_ROOT_TRANS_TAG 0
  36
  37static unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
  38	[TRANS_STATE_RUNNING]		= 0U,
  39	[TRANS_STATE_BLOCKED]		= (__TRANS_USERSPACE |
  40					   __TRANS_START),
  41	[TRANS_STATE_COMMIT_START]	= (__TRANS_USERSPACE |
  42					   __TRANS_START |
  43					   __TRANS_ATTACH),
  44	[TRANS_STATE_COMMIT_DOING]	= (__TRANS_USERSPACE |
  45					   __TRANS_START |
  46					   __TRANS_ATTACH |
  47					   __TRANS_JOIN),
  48	[TRANS_STATE_UNBLOCKED]		= (__TRANS_USERSPACE |
  49					   __TRANS_START |
  50					   __TRANS_ATTACH |
  51					   __TRANS_JOIN |
  52					   __TRANS_JOIN_NOLOCK),
  53	[TRANS_STATE_COMPLETED]		= (__TRANS_USERSPACE |
  54					   __TRANS_START |
  55					   __TRANS_ATTACH |
  56					   __TRANS_JOIN |
  57					   __TRANS_JOIN_NOLOCK),
  58};
  59
  60void btrfs_put_transaction(struct btrfs_transaction *transaction)
  61{
  62	WARN_ON(atomic_read(&transaction->use_count) == 0);
  63	if (atomic_dec_and_test(&transaction->use_count)) {
  64		BUG_ON(!list_empty(&transaction->list));
  65		WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
 
 
 
  66		while (!list_empty(&transaction->pending_chunks)) {
  67			struct extent_map *em;
  68
  69			em = list_first_entry(&transaction->pending_chunks,
  70					      struct extent_map, list);
  71			list_del_init(&em->list);
  72			free_extent_map(em);
  73		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  74		kmem_cache_free(btrfs_transaction_cachep, transaction);
  75	}
  76}
  77
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  78static noinline void switch_commit_roots(struct btrfs_transaction *trans,
  79					 struct btrfs_fs_info *fs_info)
  80{
  81	struct btrfs_root *root, *tmp;
  82
  83	down_write(&fs_info->commit_root_sem);
  84	list_for_each_entry_safe(root, tmp, &trans->switch_commits,
  85				 dirty_list) {
  86		list_del_init(&root->dirty_list);
  87		free_extent_buffer(root->commit_root);
  88		root->commit_root = btrfs_root_node(root);
  89		if (is_fstree(root->objectid))
  90			btrfs_unpin_free_ino(root);
 
  91	}
 
 
 
 
 
 
 
 
 
 
 
 
  92	up_write(&fs_info->commit_root_sem);
  93}
  94
  95static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
  96					 unsigned int type)
  97{
  98	if (type & TRANS_EXTWRITERS)
  99		atomic_inc(&trans->num_extwriters);
 100}
 101
 102static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
 103					 unsigned int type)
 104{
 105	if (type & TRANS_EXTWRITERS)
 106		atomic_dec(&trans->num_extwriters);
 107}
 108
 109static inline void extwriter_counter_init(struct btrfs_transaction *trans,
 110					  unsigned int type)
 111{
 112	atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
 113}
 114
 115static inline int extwriter_counter_read(struct btrfs_transaction *trans)
 116{
 117	return atomic_read(&trans->num_extwriters);
 118}
 119
 120/*
 121 * either allocate a new transaction or hop into the existing one
 122 */
 123static noinline int join_transaction(struct btrfs_root *root, unsigned int type)
 124{
 125	struct btrfs_transaction *cur_trans;
 126	struct btrfs_fs_info *fs_info = root->fs_info;
 127
 128	spin_lock(&fs_info->trans_lock);
 129loop:
 130	/* The file system has been taken offline. No new transactions. */
 131	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 132		spin_unlock(&fs_info->trans_lock);
 133		return -EROFS;
 134	}
 135
 136	cur_trans = fs_info->running_transaction;
 137	if (cur_trans) {
 138		if (cur_trans->aborted) {
 139			spin_unlock(&fs_info->trans_lock);
 140			return cur_trans->aborted;
 141		}
 142		if (btrfs_blocked_trans_types[cur_trans->state] & type) {
 143			spin_unlock(&fs_info->trans_lock);
 144			return -EBUSY;
 145		}
 146		atomic_inc(&cur_trans->use_count);
 147		atomic_inc(&cur_trans->num_writers);
 148		extwriter_counter_inc(cur_trans, type);
 149		spin_unlock(&fs_info->trans_lock);
 150		return 0;
 151	}
 152	spin_unlock(&fs_info->trans_lock);
 153
 154	/*
 155	 * If we are ATTACH, we just want to catch the current transaction,
 156	 * and commit it. If there is no transaction, just return ENOENT.
 157	 */
 158	if (type == TRANS_ATTACH)
 159		return -ENOENT;
 160
 161	/*
 162	 * JOIN_NOLOCK only happens during the transaction commit, so
 163	 * it is impossible that ->running_transaction is NULL
 164	 */
 165	BUG_ON(type == TRANS_JOIN_NOLOCK);
 166
 167	cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
 168	if (!cur_trans)
 169		return -ENOMEM;
 170
 171	spin_lock(&fs_info->trans_lock);
 172	if (fs_info->running_transaction) {
 173		/*
 174		 * someone started a transaction after we unlocked.  Make sure
 175		 * to redo the checks above
 176		 */
 177		kmem_cache_free(btrfs_transaction_cachep, cur_trans);
 178		goto loop;
 179	} else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 180		spin_unlock(&fs_info->trans_lock);
 181		kmem_cache_free(btrfs_transaction_cachep, cur_trans);
 182		return -EROFS;
 183	}
 184
 185	atomic_set(&cur_trans->num_writers, 1);
 186	extwriter_counter_init(cur_trans, type);
 187	init_waitqueue_head(&cur_trans->writer_wait);
 188	init_waitqueue_head(&cur_trans->commit_wait);
 
 189	cur_trans->state = TRANS_STATE_RUNNING;
 190	/*
 191	 * One for this trans handle, one so it will live on until we
 192	 * commit the transaction.
 193	 */
 194	atomic_set(&cur_trans->use_count, 2);
 
 
 195	cur_trans->start_time = get_seconds();
 196
 
 
 197	cur_trans->delayed_refs.href_root = RB_ROOT;
 
 198	atomic_set(&cur_trans->delayed_refs.num_entries, 0);
 199	cur_trans->delayed_refs.num_heads_ready = 0;
 200	cur_trans->delayed_refs.num_heads = 0;
 201	cur_trans->delayed_refs.flushing = 0;
 202	cur_trans->delayed_refs.run_delayed_start = 0;
 203
 204	/*
 205	 * although the tree mod log is per file system and not per transaction,
 206	 * the log must never go across transaction boundaries.
 207	 */
 208	smp_mb();
 209	if (!list_empty(&fs_info->tree_mod_seq_list))
 210		WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when "
 211			"creating a fresh transaction\n");
 212	if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
 213		WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when "
 214			"creating a fresh transaction\n");
 215	atomic64_set(&fs_info->tree_mod_seq, 0);
 216
 217	spin_lock_init(&cur_trans->delayed_refs.lock);
 218
 219	INIT_LIST_HEAD(&cur_trans->pending_snapshots);
 220	INIT_LIST_HEAD(&cur_trans->ordered_operations);
 221	INIT_LIST_HEAD(&cur_trans->pending_chunks);
 222	INIT_LIST_HEAD(&cur_trans->switch_commits);
 
 
 
 
 
 
 
 
 223	list_add_tail(&cur_trans->list, &fs_info->trans_list);
 224	extent_io_tree_init(&cur_trans->dirty_pages,
 225			     fs_info->btree_inode->i_mapping);
 226	fs_info->generation++;
 227	cur_trans->transid = fs_info->generation;
 228	fs_info->running_transaction = cur_trans;
 229	cur_trans->aborted = 0;
 230	spin_unlock(&fs_info->trans_lock);
 231
 232	return 0;
 233}
 234
 235/*
 236 * this does all the record keeping required to make sure that a reference
 237 * counted root is properly recorded in a given transaction.  This is required
 238 * to make sure the old root from before we joined the transaction is deleted
 239 * when the transaction commits
 240 */
 241static int record_root_in_trans(struct btrfs_trans_handle *trans,
 242			       struct btrfs_root *root)
 243{
 244	if (root->ref_cows && root->last_trans < trans->transid) {
 
 245		WARN_ON(root == root->fs_info->extent_root);
 246		WARN_ON(root->commit_root != root->node);
 247
 248		/*
 249		 * see below for in_trans_setup usage rules
 250		 * we have the reloc mutex held now, so there
 251		 * is only one writer in this function
 252		 */
 253		root->in_trans_setup = 1;
 254
 255		/* make sure readers find in_trans_setup before
 256		 * they find our root->last_trans update
 257		 */
 258		smp_wmb();
 259
 260		spin_lock(&root->fs_info->fs_roots_radix_lock);
 261		if (root->last_trans == trans->transid) {
 262			spin_unlock(&root->fs_info->fs_roots_radix_lock);
 263			return 0;
 264		}
 265		radix_tree_tag_set(&root->fs_info->fs_roots_radix,
 266			   (unsigned long)root->root_key.objectid,
 267			   BTRFS_ROOT_TRANS_TAG);
 268		spin_unlock(&root->fs_info->fs_roots_radix_lock);
 269		root->last_trans = trans->transid;
 270
 271		/* this is pretty tricky.  We don't want to
 272		 * take the relocation lock in btrfs_record_root_in_trans
 273		 * unless we're really doing the first setup for this root in
 274		 * this transaction.
 275		 *
 276		 * Normally we'd use root->last_trans as a flag to decide
 277		 * if we want to take the expensive mutex.
 278		 *
 279		 * But, we have to set root->last_trans before we
 280		 * init the relocation root, otherwise, we trip over warnings
 281		 * in ctree.c.  The solution used here is to flag ourselves
 282		 * with root->in_trans_setup.  When this is 1, we're still
 283		 * fixing up the reloc trees and everyone must wait.
 284		 *
 285		 * When this is zero, they can trust root->last_trans and fly
 286		 * through btrfs_record_root_in_trans without having to take the
 287		 * lock.  smp_wmb() makes sure that all the writes above are
 288		 * done before we pop in the zero below
 289		 */
 290		btrfs_init_reloc_root(trans, root);
 291		smp_wmb();
 292		root->in_trans_setup = 0;
 293	}
 294	return 0;
 295}
 296
 297
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 298int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
 299			       struct btrfs_root *root)
 300{
 301	if (!root->ref_cows)
 302		return 0;
 303
 304	/*
 305	 * see record_root_in_trans for comments about in_trans_setup usage
 306	 * and barriers
 307	 */
 308	smp_rmb();
 309	if (root->last_trans == trans->transid &&
 310	    !root->in_trans_setup)
 311		return 0;
 312
 313	mutex_lock(&root->fs_info->reloc_mutex);
 314	record_root_in_trans(trans, root);
 315	mutex_unlock(&root->fs_info->reloc_mutex);
 316
 317	return 0;
 318}
 319
 320static inline int is_transaction_blocked(struct btrfs_transaction *trans)
 321{
 322	return (trans->state >= TRANS_STATE_BLOCKED &&
 323		trans->state < TRANS_STATE_UNBLOCKED &&
 324		!trans->aborted);
 325}
 326
 327/* wait for commit against the current transaction to become unblocked
 328 * when this is done, it is safe to start a new transaction, but the current
 329 * transaction might not be fully on disk.
 330 */
 331static void wait_current_trans(struct btrfs_root *root)
 332{
 333	struct btrfs_transaction *cur_trans;
 334
 335	spin_lock(&root->fs_info->trans_lock);
 336	cur_trans = root->fs_info->running_transaction;
 337	if (cur_trans && is_transaction_blocked(cur_trans)) {
 338		atomic_inc(&cur_trans->use_count);
 339		spin_unlock(&root->fs_info->trans_lock);
 340
 341		wait_event(root->fs_info->transaction_wait,
 342			   cur_trans->state >= TRANS_STATE_UNBLOCKED ||
 343			   cur_trans->aborted);
 344		btrfs_put_transaction(cur_trans);
 345	} else {
 346		spin_unlock(&root->fs_info->trans_lock);
 347	}
 348}
 349
 350static int may_wait_transaction(struct btrfs_root *root, int type)
 351{
 352	if (root->fs_info->log_root_recovering)
 353		return 0;
 354
 355	if (type == TRANS_USERSPACE)
 356		return 1;
 357
 358	if (type == TRANS_START &&
 359	    !atomic_read(&root->fs_info->open_ioctl_trans))
 360		return 1;
 361
 362	return 0;
 363}
 364
 365static inline bool need_reserve_reloc_root(struct btrfs_root *root)
 366{
 367	if (!root->fs_info->reloc_ctl ||
 368	    !root->ref_cows ||
 369	    root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
 370	    root->reloc_root)
 371		return false;
 372
 373	return true;
 374}
 375
 376static struct btrfs_trans_handle *
 377start_transaction(struct btrfs_root *root, u64 num_items, unsigned int type,
 378		  enum btrfs_reserve_flush_enum flush)
 379{
 380	struct btrfs_trans_handle *h;
 381	struct btrfs_transaction *cur_trans;
 382	u64 num_bytes = 0;
 383	u64 qgroup_reserved = 0;
 384	bool reloc_reserved = false;
 385	int ret;
 386
 
 
 
 387	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
 388		return ERR_PTR(-EROFS);
 389
 390	if (current->journal_info &&
 391	    current->journal_info != (void *)BTRFS_SEND_TRANS_STUB) {
 392		WARN_ON(type & TRANS_EXTWRITERS);
 393		h = current->journal_info;
 394		h->use_count++;
 395		WARN_ON(h->use_count > 2);
 396		h->orig_rsv = h->block_rsv;
 397		h->block_rsv = NULL;
 398		goto got_it;
 399	}
 400
 401	/*
 402	 * Do the reservation before we join the transaction so we can do all
 403	 * the appropriate flushing if need be.
 404	 */
 405	if (num_items > 0 && root != root->fs_info->chunk_root) {
 406		if (root->fs_info->quota_enabled &&
 407		    is_fstree(root->root_key.objectid)) {
 408			qgroup_reserved = num_items * root->leafsize;
 409			ret = btrfs_qgroup_reserve(root, qgroup_reserved);
 410			if (ret)
 411				return ERR_PTR(ret);
 412		}
 413
 414		num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
 415		/*
 416		 * Do the reservation for the relocation root creation
 417		 */
 418		if (unlikely(need_reserve_reloc_root(root))) {
 419			num_bytes += root->nodesize;
 420			reloc_reserved = true;
 421		}
 422
 423		ret = btrfs_block_rsv_add(root,
 424					  &root->fs_info->trans_block_rsv,
 425					  num_bytes, flush);
 426		if (ret)
 427			goto reserve_fail;
 428	}
 429again:
 430	h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 431	if (!h) {
 432		ret = -ENOMEM;
 433		goto alloc_fail;
 434	}
 435
 436	/*
 437	 * If we are JOIN_NOLOCK we're already committing a transaction and
 438	 * waiting on this guy, so we don't need to do the sb_start_intwrite
 439	 * because we're already holding a ref.  We need this because we could
 440	 * have raced in and did an fsync() on a file which can kick a commit
 441	 * and then we deadlock with somebody doing a freeze.
 442	 *
 443	 * If we are ATTACH, it means we just want to catch the current
 444	 * transaction and commit it, so we needn't do sb_start_intwrite(). 
 445	 */
 446	if (type & __TRANS_FREEZABLE)
 447		sb_start_intwrite(root->fs_info->sb);
 448
 449	if (may_wait_transaction(root, type))
 450		wait_current_trans(root);
 451
 452	do {
 453		ret = join_transaction(root, type);
 454		if (ret == -EBUSY) {
 455			wait_current_trans(root);
 456			if (unlikely(type == TRANS_ATTACH))
 457				ret = -ENOENT;
 458		}
 459	} while (ret == -EBUSY);
 460
 461	if (ret < 0) {
 462		/* We must get the transaction if we are JOIN_NOLOCK. */
 463		BUG_ON(type == TRANS_JOIN_NOLOCK);
 464		goto join_fail;
 465	}
 466
 467	cur_trans = root->fs_info->running_transaction;
 468
 469	h->transid = cur_trans->transid;
 470	h->transaction = cur_trans;
 471	h->blocks_used = 0;
 472	h->bytes_reserved = 0;
 473	h->root = root;
 474	h->delayed_ref_updates = 0;
 475	h->use_count = 1;
 476	h->adding_csums = 0;
 477	h->block_rsv = NULL;
 478	h->orig_rsv = NULL;
 479	h->aborted = 0;
 480	h->qgroup_reserved = 0;
 481	h->delayed_ref_elem.seq = 0;
 482	h->type = type;
 483	h->allocating_chunk = false;
 484	h->reloc_reserved = false;
 485	h->sync = false;
 486	INIT_LIST_HEAD(&h->qgroup_ref_list);
 487	INIT_LIST_HEAD(&h->new_bgs);
 488
 489	smp_mb();
 490	if (cur_trans->state >= TRANS_STATE_BLOCKED &&
 491	    may_wait_transaction(root, type)) {
 
 492		btrfs_commit_transaction(h, root);
 493		goto again;
 494	}
 495
 496	if (num_bytes) {
 497		trace_btrfs_space_reservation(root->fs_info, "transaction",
 498					      h->transid, num_bytes, 1);
 499		h->block_rsv = &root->fs_info->trans_block_rsv;
 500		h->bytes_reserved = num_bytes;
 501		h->reloc_reserved = reloc_reserved;
 502	}
 503	h->qgroup_reserved = qgroup_reserved;
 504
 505got_it:
 506	btrfs_record_root_in_trans(h, root);
 507
 508	if (!current->journal_info && type != TRANS_USERSPACE)
 509		current->journal_info = h;
 510	return h;
 511
 512join_fail:
 513	if (type & __TRANS_FREEZABLE)
 514		sb_end_intwrite(root->fs_info->sb);
 515	kmem_cache_free(btrfs_trans_handle_cachep, h);
 516alloc_fail:
 517	if (num_bytes)
 518		btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv,
 519					num_bytes);
 520reserve_fail:
 521	if (qgroup_reserved)
 522		btrfs_qgroup_free(root, qgroup_reserved);
 523	return ERR_PTR(ret);
 524}
 525
 526struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 527						   int num_items)
 528{
 529	return start_transaction(root, num_items, TRANS_START,
 530				 BTRFS_RESERVE_FLUSH_ALL);
 531}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 532
 533struct btrfs_trans_handle *btrfs_start_transaction_lflush(
 534					struct btrfs_root *root, int num_items)
 
 535{
 536	return start_transaction(root, num_items, TRANS_START,
 537				 BTRFS_RESERVE_FLUSH_LIMIT);
 538}
 539
 540struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
 541{
 542	return start_transaction(root, 0, TRANS_JOIN, 0);
 
 543}
 544
 545struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
 546{
 547	return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 0);
 
 548}
 549
 550struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
 551{
 552	return start_transaction(root, 0, TRANS_USERSPACE, 0);
 
 553}
 554
 555/*
 556 * btrfs_attach_transaction() - catch the running transaction
 557 *
 558 * It is used when we want to commit the current the transaction, but
 559 * don't want to start a new one.
 560 *
 561 * Note: If this function return -ENOENT, it just means there is no
 562 * running transaction. But it is possible that the inactive transaction
 563 * is still in the memory, not fully on disk. If you hope there is no
 564 * inactive transaction in the fs when -ENOENT is returned, you should
 565 * invoke
 566 *     btrfs_attach_transaction_barrier()
 567 */
 568struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
 569{
 570	return start_transaction(root, 0, TRANS_ATTACH, 0);
 
 571}
 572
 573/*
 574 * btrfs_attach_transaction_barrier() - catch the running transaction
 575 *
 576 * It is similar to the above function, the differentia is this one
 577 * will wait for all the inactive transactions until they fully
 578 * complete.
 579 */
 580struct btrfs_trans_handle *
 581btrfs_attach_transaction_barrier(struct btrfs_root *root)
 582{
 583	struct btrfs_trans_handle *trans;
 584
 585	trans = start_transaction(root, 0, TRANS_ATTACH, 0);
 
 586	if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT)
 587		btrfs_wait_for_commit(root, 0);
 588
 589	return trans;
 590}
 591
 592/* wait for a transaction commit to be fully complete */
 593static noinline void wait_for_commit(struct btrfs_root *root,
 594				    struct btrfs_transaction *commit)
 595{
 596	wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED);
 597}
 598
 599int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
 600{
 601	struct btrfs_transaction *cur_trans = NULL, *t;
 602	int ret = 0;
 603
 604	if (transid) {
 605		if (transid <= root->fs_info->last_trans_committed)
 606			goto out;
 607
 608		ret = -EINVAL;
 609		/* find specified transaction */
 610		spin_lock(&root->fs_info->trans_lock);
 611		list_for_each_entry(t, &root->fs_info->trans_list, list) {
 612			if (t->transid == transid) {
 613				cur_trans = t;
 614				atomic_inc(&cur_trans->use_count);
 615				ret = 0;
 616				break;
 617			}
 618			if (t->transid > transid) {
 619				ret = 0;
 620				break;
 621			}
 622		}
 623		spin_unlock(&root->fs_info->trans_lock);
 624		/* The specified transaction doesn't exist */
 625		if (!cur_trans)
 
 
 
 
 
 
 626			goto out;
 
 627	} else {
 628		/* find newest transaction that is committing | committed */
 629		spin_lock(&root->fs_info->trans_lock);
 630		list_for_each_entry_reverse(t, &root->fs_info->trans_list,
 631					    list) {
 632			if (t->state >= TRANS_STATE_COMMIT_START) {
 633				if (t->state == TRANS_STATE_COMPLETED)
 634					break;
 635				cur_trans = t;
 636				atomic_inc(&cur_trans->use_count);
 637				break;
 638			}
 639		}
 640		spin_unlock(&root->fs_info->trans_lock);
 641		if (!cur_trans)
 642			goto out;  /* nothing committing|committed */
 643	}
 644
 645	wait_for_commit(root, cur_trans);
 646	btrfs_put_transaction(cur_trans);
 647out:
 648	return ret;
 649}
 650
 651void btrfs_throttle(struct btrfs_root *root)
 652{
 653	if (!atomic_read(&root->fs_info->open_ioctl_trans))
 654		wait_current_trans(root);
 655}
 656
 657static int should_end_transaction(struct btrfs_trans_handle *trans,
 658				  struct btrfs_root *root)
 659{
 660	if (root->fs_info->global_block_rsv.space_info->full &&
 661	    btrfs_check_space_for_delayed_refs(trans, root))
 662		return 1;
 663
 664	return !!btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
 665}
 666
 667int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
 668				 struct btrfs_root *root)
 669{
 670	struct btrfs_transaction *cur_trans = trans->transaction;
 671	int updates;
 672	int err;
 673
 674	smp_mb();
 675	if (cur_trans->state >= TRANS_STATE_BLOCKED ||
 676	    cur_trans->delayed_refs.flushing)
 677		return 1;
 678
 679	updates = trans->delayed_ref_updates;
 680	trans->delayed_ref_updates = 0;
 681	if (updates) {
 682		err = btrfs_run_delayed_refs(trans, root, updates);
 683		if (err) /* Error code will also eval true */
 684			return err;
 685	}
 686
 687	return should_end_transaction(trans, root);
 688}
 689
 690static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 691			  struct btrfs_root *root, int throttle)
 692{
 693	struct btrfs_transaction *cur_trans = trans->transaction;
 694	struct btrfs_fs_info *info = root->fs_info;
 695	unsigned long cur = trans->delayed_ref_updates;
 696	int lock = (trans->type != TRANS_JOIN_NOLOCK);
 697	int err = 0;
 
 698
 699	if (trans->use_count > 1) {
 700		trans->use_count--;
 701		trans->block_rsv = trans->orig_rsv;
 702		return 0;
 703	}
 704
 705	/*
 706	 * do the qgroup accounting as early as possible
 707	 */
 708	err = btrfs_delayed_refs_qgroup_accounting(trans, info);
 709
 710	btrfs_trans_release_metadata(trans, root);
 711	trans->block_rsv = NULL;
 712
 713	if (trans->qgroup_reserved) {
 714		/*
 715		 * the same root has to be passed here between start_transaction
 716		 * and end_transaction. Subvolume quota depends on this.
 717		 */
 718		btrfs_qgroup_free(trans->root, trans->qgroup_reserved);
 719		trans->qgroup_reserved = 0;
 720	}
 721
 722	if (!list_empty(&trans->new_bgs))
 723		btrfs_create_pending_block_groups(trans, root);
 724
 725	trans->delayed_ref_updates = 0;
 726	if (!trans->sync && btrfs_should_throttle_delayed_refs(trans, root)) {
 
 
 727		cur = max_t(unsigned long, cur, 32);
 728		trans->delayed_ref_updates = 0;
 729		btrfs_run_delayed_refs(trans, root, cur);
 
 
 
 
 
 
 730	}
 731
 732	btrfs_trans_release_metadata(trans, root);
 733	trans->block_rsv = NULL;
 734
 735	if (!list_empty(&trans->new_bgs))
 736		btrfs_create_pending_block_groups(trans, root);
 737
 
 
 738	if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
 739	    should_end_transaction(trans, root) &&
 740	    ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) {
 741		spin_lock(&info->trans_lock);
 742		if (cur_trans->state == TRANS_STATE_RUNNING)
 743			cur_trans->state = TRANS_STATE_BLOCKED;
 744		spin_unlock(&info->trans_lock);
 745	}
 746
 747	if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
 748		if (throttle)
 749			return btrfs_commit_transaction(trans, root);
 750		else
 751			wake_up_process(info->transaction_kthread);
 752	}
 753
 754	if (trans->type & __TRANS_FREEZABLE)
 755		sb_end_intwrite(root->fs_info->sb);
 756
 757	WARN_ON(cur_trans != info->running_transaction);
 758	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
 759	atomic_dec(&cur_trans->num_writers);
 760	extwriter_counter_dec(cur_trans, trans->type);
 761
 
 
 
 762	smp_mb();
 763	if (waitqueue_active(&cur_trans->writer_wait))
 764		wake_up(&cur_trans->writer_wait);
 765	btrfs_put_transaction(cur_trans);
 766
 767	if (current->journal_info == trans)
 768		current->journal_info = NULL;
 769
 770	if (throttle)
 771		btrfs_run_delayed_iputs(root);
 772
 773	if (trans->aborted ||
 774	    test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
 775		wake_up_process(info->transaction_kthread);
 776		err = -EIO;
 777	}
 778	assert_qgroups_uptodate(trans);
 779
 780	kmem_cache_free(btrfs_trans_handle_cachep, trans);
 
 
 
 
 781	return err;
 782}
 783
 784int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 785			  struct btrfs_root *root)
 786{
 787	return __btrfs_end_transaction(trans, root, 0);
 788}
 789
 790int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
 791				   struct btrfs_root *root)
 792{
 793	return __btrfs_end_transaction(trans, root, 1);
 794}
 795
 796/*
 797 * when btree blocks are allocated, they have some corresponding bits set for
 798 * them in one of two extent_io trees.  This is used to make sure all of
 799 * those extents are sent to disk but does not wait on them
 800 */
 801int btrfs_write_marked_extents(struct btrfs_root *root,
 802			       struct extent_io_tree *dirty_pages, int mark)
 803{
 804	int err = 0;
 805	int werr = 0;
 806	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 807	struct extent_state *cached_state = NULL;
 808	u64 start = 0;
 809	u64 end;
 810
 811	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
 812				      mark, &cached_state)) {
 813		convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
 814				   mark, &cached_state, GFP_NOFS);
 815		cached_state = NULL;
 816		err = filemap_fdatawrite_range(mapping, start, end);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 817		if (err)
 818			werr = err;
 
 
 
 
 819		cond_resched();
 820		start = end + 1;
 821	}
 822	if (err)
 823		werr = err;
 824	return werr;
 825}
 826
 827/*
 828 * when btree blocks are allocated, they have some corresponding bits set for
 829 * them in one of two extent_io trees.  This is used to make sure all of
 830 * those extents are on disk for transaction or log commit.  We wait
 831 * on all the pages and clear them from the dirty pages state tree
 832 */
 833int btrfs_wait_marked_extents(struct btrfs_root *root,
 834			      struct extent_io_tree *dirty_pages, int mark)
 835{
 836	int err = 0;
 837	int werr = 0;
 838	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 839	struct extent_state *cached_state = NULL;
 840	u64 start = 0;
 841	u64 end;
 
 
 842
 843	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
 844				      EXTENT_NEED_WAIT, &cached_state)) {
 845		clear_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
 846				 0, 0, &cached_state, GFP_NOFS);
 847		err = filemap_fdatawait_range(mapping, start, end);
 
 
 
 
 
 
 
 
 
 
 
 
 848		if (err)
 849			werr = err;
 
 
 850		cond_resched();
 851		start = end + 1;
 852	}
 853	if (err)
 854		werr = err;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 855	return werr;
 856}
 857
 858/*
 859 * when btree blocks are allocated, they have some corresponding bits set for
 860 * them in one of two extent_io trees.  This is used to make sure all of
 861 * those extents are on disk for transaction or log commit
 862 */
 863static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
 864				struct extent_io_tree *dirty_pages, int mark)
 865{
 866	int ret;
 867	int ret2;
 868	struct blk_plug plug;
 869
 870	blk_start_plug(&plug);
 871	ret = btrfs_write_marked_extents(root, dirty_pages, mark);
 872	blk_finish_plug(&plug);
 873	ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
 874
 875	if (ret)
 876		return ret;
 877	if (ret2)
 878		return ret2;
 879	return 0;
 880}
 881
 882int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 883				     struct btrfs_root *root)
 884{
 885	if (!trans || !trans->transaction) {
 886		struct inode *btree_inode;
 887		btree_inode = root->fs_info->btree_inode;
 888		return filemap_write_and_wait(btree_inode->i_mapping);
 889	}
 890	return btrfs_write_and_wait_marked_extents(root,
 891					   &trans->transaction->dirty_pages,
 892					   EXTENT_DIRTY);
 
 
 
 893}
 894
 895/*
 896 * this is used to update the root pointer in the tree of tree roots.
 897 *
 898 * But, in the case of the extent allocation tree, updating the root
 899 * pointer may allocate blocks which may change the root of the extent
 900 * allocation tree.
 901 *
 902 * So, this loops and repeats and makes sure the cowonly root didn't
 903 * change while the root pointer was being updated in the metadata.
 904 */
 905static int update_cowonly_root(struct btrfs_trans_handle *trans,
 906			       struct btrfs_root *root)
 907{
 908	int ret;
 909	u64 old_root_bytenr;
 910	u64 old_root_used;
 911	struct btrfs_root *tree_root = root->fs_info->tree_root;
 912
 913	old_root_used = btrfs_root_used(&root->root_item);
 914	btrfs_write_dirty_block_groups(trans, root);
 915
 916	while (1) {
 917		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
 918		if (old_root_bytenr == root->node->start &&
 919		    old_root_used == btrfs_root_used(&root->root_item))
 920			break;
 921
 922		btrfs_set_root_node(&root->root_item, root->node);
 923		ret = btrfs_update_root(trans, tree_root,
 924					&root->root_key,
 925					&root->root_item);
 926		if (ret)
 927			return ret;
 928
 929		old_root_used = btrfs_root_used(&root->root_item);
 930		ret = btrfs_write_dirty_block_groups(trans, root);
 931		if (ret)
 932			return ret;
 933	}
 934
 935	return 0;
 936}
 937
 938/*
 939 * update all the cowonly tree roots on disk
 940 *
 941 * The error handling in this function may not be obvious. Any of the
 942 * failures will cause the file system to go offline. We still need
 943 * to clean up the delayed refs.
 944 */
 945static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
 946					 struct btrfs_root *root)
 947{
 948	struct btrfs_fs_info *fs_info = root->fs_info;
 
 
 949	struct list_head *next;
 950	struct extent_buffer *eb;
 951	int ret;
 952
 953	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
 954	if (ret)
 955		return ret;
 956
 957	eb = btrfs_lock_root_node(fs_info->tree_root);
 958	ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
 959			      0, &eb);
 960	btrfs_tree_unlock(eb);
 961	free_extent_buffer(eb);
 962
 963	if (ret)
 964		return ret;
 965
 966	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
 967	if (ret)
 968		return ret;
 969
 970	ret = btrfs_run_dev_stats(trans, root->fs_info);
 971	if (ret)
 972		return ret;
 973	ret = btrfs_run_dev_replace(trans, root->fs_info);
 974	if (ret)
 975		return ret;
 976	ret = btrfs_run_qgroups(trans, root->fs_info);
 977	if (ret)
 978		return ret;
 979
 
 
 
 
 980	/* run_qgroups might have added some more refs */
 981	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
 982	if (ret)
 983		return ret;
 984
 985	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
 986		next = fs_info->dirty_cowonly_roots.next;
 987		list_del_init(next);
 988		root = list_entry(next, struct btrfs_root, dirty_list);
 
 989
 990		if (root != fs_info->extent_root)
 991			list_add_tail(&root->dirty_list,
 992				      &trans->transaction->switch_commits);
 993		ret = update_cowonly_root(trans, root);
 994		if (ret)
 995			return ret;
 
 
 
 996	}
 997
 
 
 
 
 
 
 
 
 
 
 
 
 998	list_add_tail(&fs_info->extent_root->dirty_list,
 999		      &trans->transaction->switch_commits);
1000	btrfs_after_dev_replace_commit(fs_info);
1001
1002	return 0;
1003}
1004
1005/*
1006 * dead roots are old snapshots that need to be deleted.  This allocates
1007 * a dirty root struct and adds it into the list of dead roots that need to
1008 * be deleted
1009 */
1010void btrfs_add_dead_root(struct btrfs_root *root)
1011{
1012	spin_lock(&root->fs_info->trans_lock);
1013	if (list_empty(&root->root_list))
1014		list_add_tail(&root->root_list, &root->fs_info->dead_roots);
1015	spin_unlock(&root->fs_info->trans_lock);
1016}
1017
1018/*
1019 * update all the cowonly tree roots on disk
1020 */
1021static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
1022				    struct btrfs_root *root)
1023{
1024	struct btrfs_root *gang[8];
1025	struct btrfs_fs_info *fs_info = root->fs_info;
1026	int i;
1027	int ret;
1028	int err = 0;
1029
1030	spin_lock(&fs_info->fs_roots_radix_lock);
1031	while (1) {
1032		ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1033						 (void **)gang, 0,
1034						 ARRAY_SIZE(gang),
1035						 BTRFS_ROOT_TRANS_TAG);
1036		if (ret == 0)
1037			break;
1038		for (i = 0; i < ret; i++) {
1039			root = gang[i];
1040			radix_tree_tag_clear(&fs_info->fs_roots_radix,
1041					(unsigned long)root->root_key.objectid,
1042					BTRFS_ROOT_TRANS_TAG);
1043			spin_unlock(&fs_info->fs_roots_radix_lock);
1044
1045			btrfs_free_log(trans, root);
1046			btrfs_update_reloc_root(trans, root);
1047			btrfs_orphan_commit_root(trans, root);
1048
1049			btrfs_save_ino_cache(root, trans);
1050
1051			/* see comments in should_cow_block() */
1052			root->force_cow = 0;
1053			smp_wmb();
1054
1055			if (root->commit_root != root->node) {
1056				list_add_tail(&root->dirty_list,
1057					&trans->transaction->switch_commits);
1058				btrfs_set_root_node(&root->root_item,
1059						    root->node);
1060			}
1061
1062			err = btrfs_update_root(trans, fs_info->tree_root,
1063						&root->root_key,
1064						&root->root_item);
1065			spin_lock(&fs_info->fs_roots_radix_lock);
1066			if (err)
1067				break;
 
1068		}
1069	}
1070	spin_unlock(&fs_info->fs_roots_radix_lock);
1071	return err;
1072}
1073
1074/*
1075 * defrag a given btree.
1076 * Every leaf in the btree is read and defragged.
1077 */
1078int btrfs_defrag_root(struct btrfs_root *root)
1079{
1080	struct btrfs_fs_info *info = root->fs_info;
1081	struct btrfs_trans_handle *trans;
1082	int ret;
1083
1084	if (xchg(&root->defrag_running, 1))
1085		return 0;
1086
1087	while (1) {
1088		trans = btrfs_start_transaction(root, 0);
1089		if (IS_ERR(trans))
1090			return PTR_ERR(trans);
1091
1092		ret = btrfs_defrag_leaves(trans, root);
1093
1094		btrfs_end_transaction(trans, root);
1095		btrfs_btree_balance_dirty(info->tree_root);
1096		cond_resched();
1097
1098		if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
1099			break;
1100
1101		if (btrfs_defrag_cancelled(root->fs_info)) {
1102			pr_debug("BTRFS: defrag_root cancelled\n");
1103			ret = -EAGAIN;
1104			break;
1105		}
1106	}
1107	root->defrag_running = 0;
1108	return ret;
1109}
1110
1111/*
1112 * new snapshots need to be created at a very specific time in the
1113 * transaction commit.  This does the actual creation.
1114 *
1115 * Note:
1116 * If the error which may affect the commitment of the current transaction
1117 * happens, we should return the error number. If the error which just affect
1118 * the creation of the pending snapshots, just return 0.
1119 */
1120static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1121				   struct btrfs_fs_info *fs_info,
1122				   struct btrfs_pending_snapshot *pending)
1123{
1124	struct btrfs_key key;
1125	struct btrfs_root_item *new_root_item;
1126	struct btrfs_root *tree_root = fs_info->tree_root;
1127	struct btrfs_root *root = pending->root;
1128	struct btrfs_root *parent_root;
1129	struct btrfs_block_rsv *rsv;
1130	struct inode *parent_inode;
1131	struct btrfs_path *path;
1132	struct btrfs_dir_item *dir_item;
1133	struct dentry *dentry;
1134	struct extent_buffer *tmp;
1135	struct extent_buffer *old;
1136	struct timespec cur_time = CURRENT_TIME;
1137	int ret = 0;
1138	u64 to_reserve = 0;
1139	u64 index = 0;
1140	u64 objectid;
1141	u64 root_flags;
1142	uuid_le new_uuid;
1143
1144	path = btrfs_alloc_path();
1145	if (!path) {
1146		pending->error = -ENOMEM;
1147		return 0;
1148	}
1149
1150	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
1151	if (!new_root_item) {
1152		pending->error = -ENOMEM;
1153		goto root_item_alloc_fail;
1154	}
1155
1156	pending->error = btrfs_find_free_objectid(tree_root, &objectid);
1157	if (pending->error)
1158		goto no_free_objectid;
1159
1160	btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
 
 
 
 
 
 
1161
1162	if (to_reserve > 0) {
1163		pending->error = btrfs_block_rsv_add(root,
1164						     &pending->block_rsv,
1165						     to_reserve,
1166						     BTRFS_RESERVE_NO_FLUSH);
1167		if (pending->error)
1168			goto no_free_objectid;
1169	}
1170
1171	pending->error = btrfs_qgroup_inherit(trans, fs_info,
1172					      root->root_key.objectid,
1173					      objectid, pending->inherit);
1174	if (pending->error)
1175		goto no_free_objectid;
1176
1177	key.objectid = objectid;
1178	key.offset = (u64)-1;
1179	key.type = BTRFS_ROOT_ITEM_KEY;
1180
1181	rsv = trans->block_rsv;
1182	trans->block_rsv = &pending->block_rsv;
1183	trans->bytes_reserved = trans->block_rsv->reserved;
1184
 
 
1185	dentry = pending->dentry;
1186	parent_inode = pending->dir;
1187	parent_root = BTRFS_I(parent_inode)->root;
1188	record_root_in_trans(trans, parent_root);
1189
 
 
1190	/*
1191	 * insert the directory item
1192	 */
1193	ret = btrfs_set_inode_index(parent_inode, &index);
1194	BUG_ON(ret); /* -ENOMEM */
1195
1196	/* check if there is a file/dir which has the same name. */
1197	dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1198					 btrfs_ino(parent_inode),
1199					 dentry->d_name.name,
1200					 dentry->d_name.len, 0);
1201	if (dir_item != NULL && !IS_ERR(dir_item)) {
1202		pending->error = -EEXIST;
1203		goto dir_item_existed;
1204	} else if (IS_ERR(dir_item)) {
1205		ret = PTR_ERR(dir_item);
1206		btrfs_abort_transaction(trans, root, ret);
1207		goto fail;
1208	}
1209	btrfs_release_path(path);
1210
1211	/*
1212	 * pull in the delayed directory update
1213	 * and the delayed inode item
1214	 * otherwise we corrupt the FS during
1215	 * snapshot
1216	 */
1217	ret = btrfs_run_delayed_items(trans, root);
1218	if (ret) {	/* Transaction aborted */
1219		btrfs_abort_transaction(trans, root, ret);
1220		goto fail;
1221	}
1222
1223	record_root_in_trans(trans, root);
1224	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1225	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1226	btrfs_check_and_init_root_item(new_root_item);
1227
1228	root_flags = btrfs_root_flags(new_root_item);
1229	if (pending->readonly)
1230		root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1231	else
1232		root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1233	btrfs_set_root_flags(new_root_item, root_flags);
1234
1235	btrfs_set_root_generation_v2(new_root_item,
1236			trans->transid);
1237	uuid_le_gen(&new_uuid);
1238	memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
1239	memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1240			BTRFS_UUID_SIZE);
1241	if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1242		memset(new_root_item->received_uuid, 0,
1243		       sizeof(new_root_item->received_uuid));
1244		memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1245		memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1246		btrfs_set_root_stransid(new_root_item, 0);
1247		btrfs_set_root_rtransid(new_root_item, 0);
1248	}
1249	btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1250	btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1251	btrfs_set_root_otransid(new_root_item, trans->transid);
1252
1253	old = btrfs_lock_root_node(root);
1254	ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1255	if (ret) {
1256		btrfs_tree_unlock(old);
1257		free_extent_buffer(old);
1258		btrfs_abort_transaction(trans, root, ret);
1259		goto fail;
1260	}
1261
1262	btrfs_set_lock_blocking(old);
1263
1264	ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1265	/* clean up in any case */
1266	btrfs_tree_unlock(old);
1267	free_extent_buffer(old);
1268	if (ret) {
1269		btrfs_abort_transaction(trans, root, ret);
1270		goto fail;
1271	}
1272
1273	/* see comments in should_cow_block() */
1274	root->force_cow = 1;
1275	smp_wmb();
1276
1277	btrfs_set_root_node(new_root_item, tmp);
1278	/* record when the snapshot was created in key.offset */
1279	key.offset = trans->transid;
1280	ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1281	btrfs_tree_unlock(tmp);
1282	free_extent_buffer(tmp);
1283	if (ret) {
1284		btrfs_abort_transaction(trans, root, ret);
1285		goto fail;
1286	}
1287
1288	/*
1289	 * insert root back/forward references
1290	 */
1291	ret = btrfs_add_root_ref(trans, tree_root, objectid,
1292				 parent_root->root_key.objectid,
1293				 btrfs_ino(parent_inode), index,
1294				 dentry->d_name.name, dentry->d_name.len);
1295	if (ret) {
1296		btrfs_abort_transaction(trans, root, ret);
1297		goto fail;
1298	}
1299
1300	key.offset = (u64)-1;
1301	pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1302	if (IS_ERR(pending->snap)) {
1303		ret = PTR_ERR(pending->snap);
1304		btrfs_abort_transaction(trans, root, ret);
1305		goto fail;
1306	}
1307
1308	ret = btrfs_reloc_post_snapshot(trans, pending);
1309	if (ret) {
1310		btrfs_abort_transaction(trans, root, ret);
1311		goto fail;
1312	}
1313
1314	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1315	if (ret) {
1316		btrfs_abort_transaction(trans, root, ret);
1317		goto fail;
1318	}
1319
1320	ret = btrfs_insert_dir_item(trans, parent_root,
1321				    dentry->d_name.name, dentry->d_name.len,
1322				    parent_inode, &key,
1323				    BTRFS_FT_DIR, index);
1324	/* We have check then name at the beginning, so it is impossible. */
1325	BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1326	if (ret) {
1327		btrfs_abort_transaction(trans, root, ret);
1328		goto fail;
1329	}
1330
1331	btrfs_i_size_write(parent_inode, parent_inode->i_size +
1332					 dentry->d_name.len * 2);
1333	parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
 
1334	ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
1335	if (ret) {
1336		btrfs_abort_transaction(trans, root, ret);
1337		goto fail;
1338	}
1339	ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_uuid.b,
1340				  BTRFS_UUID_KEY_SUBVOL, objectid);
1341	if (ret) {
1342		btrfs_abort_transaction(trans, root, ret);
1343		goto fail;
1344	}
1345	if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1346		ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
1347					  new_root_item->received_uuid,
1348					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1349					  objectid);
1350		if (ret && ret != -EEXIST) {
1351			btrfs_abort_transaction(trans, root, ret);
1352			goto fail;
1353		}
1354	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1355fail:
1356	pending->error = ret;
1357dir_item_existed:
1358	trans->block_rsv = rsv;
1359	trans->bytes_reserved = 0;
 
 
1360no_free_objectid:
1361	kfree(new_root_item);
1362root_item_alloc_fail:
1363	btrfs_free_path(path);
 
 
1364	return ret;
1365}
1366
1367/*
1368 * create all the snapshots we've scheduled for creation
1369 */
1370static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1371					     struct btrfs_fs_info *fs_info)
1372{
1373	struct btrfs_pending_snapshot *pending, *next;
1374	struct list_head *head = &trans->transaction->pending_snapshots;
1375	int ret = 0;
1376
1377	list_for_each_entry_safe(pending, next, head, list) {
1378		list_del(&pending->list);
1379		ret = create_pending_snapshot(trans, fs_info, pending);
1380		if (ret)
1381			break;
1382	}
1383	return ret;
1384}
1385
1386static void update_super_roots(struct btrfs_root *root)
1387{
1388	struct btrfs_root_item *root_item;
1389	struct btrfs_super_block *super;
1390
1391	super = root->fs_info->super_copy;
1392
1393	root_item = &root->fs_info->chunk_root->root_item;
1394	super->chunk_root = root_item->bytenr;
1395	super->chunk_root_generation = root_item->generation;
1396	super->chunk_root_level = root_item->level;
1397
1398	root_item = &root->fs_info->tree_root->root_item;
1399	super->root = root_item->bytenr;
1400	super->generation = root_item->generation;
1401	super->root_level = root_item->level;
1402	if (btrfs_test_opt(root, SPACE_CACHE))
1403		super->cache_generation = root_item->generation;
1404	if (root->fs_info->update_uuid_tree_gen)
1405		super->uuid_tree_generation = root_item->generation;
1406}
1407
1408int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1409{
1410	struct btrfs_transaction *trans;
1411	int ret = 0;
1412
1413	spin_lock(&info->trans_lock);
1414	trans = info->running_transaction;
1415	if (trans)
1416		ret = (trans->state >= TRANS_STATE_COMMIT_START);
1417	spin_unlock(&info->trans_lock);
1418	return ret;
1419}
1420
1421int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1422{
1423	struct btrfs_transaction *trans;
1424	int ret = 0;
1425
1426	spin_lock(&info->trans_lock);
1427	trans = info->running_transaction;
1428	if (trans)
1429		ret = is_transaction_blocked(trans);
1430	spin_unlock(&info->trans_lock);
1431	return ret;
1432}
1433
1434/*
1435 * wait for the current transaction commit to start and block subsequent
1436 * transaction joins
1437 */
1438static void wait_current_trans_commit_start(struct btrfs_root *root,
1439					    struct btrfs_transaction *trans)
1440{
1441	wait_event(root->fs_info->transaction_blocked_wait,
1442		   trans->state >= TRANS_STATE_COMMIT_START ||
1443		   trans->aborted);
1444}
1445
1446/*
1447 * wait for the current transaction to start and then become unblocked.
1448 * caller holds ref.
1449 */
1450static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1451					 struct btrfs_transaction *trans)
1452{
1453	wait_event(root->fs_info->transaction_wait,
1454		   trans->state >= TRANS_STATE_UNBLOCKED ||
1455		   trans->aborted);
1456}
1457
1458/*
1459 * commit transactions asynchronously. once btrfs_commit_transaction_async
1460 * returns, any subsequent transaction will not be allowed to join.
1461 */
1462struct btrfs_async_commit {
1463	struct btrfs_trans_handle *newtrans;
1464	struct btrfs_root *root;
1465	struct work_struct work;
1466};
1467
1468static void do_async_commit(struct work_struct *work)
1469{
1470	struct btrfs_async_commit *ac =
1471		container_of(work, struct btrfs_async_commit, work);
1472
1473	/*
1474	 * We've got freeze protection passed with the transaction.
1475	 * Tell lockdep about it.
1476	 */
1477	if (ac->newtrans->type & __TRANS_FREEZABLE)
1478		rwsem_acquire_read(
1479		     &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
1480		     0, 1, _THIS_IP_);
1481
1482	current->journal_info = ac->newtrans;
1483
1484	btrfs_commit_transaction(ac->newtrans, ac->root);
1485	kfree(ac);
1486}
1487
1488int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1489				   struct btrfs_root *root,
1490				   int wait_for_unblock)
1491{
1492	struct btrfs_async_commit *ac;
1493	struct btrfs_transaction *cur_trans;
1494
1495	ac = kmalloc(sizeof(*ac), GFP_NOFS);
1496	if (!ac)
1497		return -ENOMEM;
1498
1499	INIT_WORK(&ac->work, do_async_commit);
1500	ac->root = root;
1501	ac->newtrans = btrfs_join_transaction(root);
1502	if (IS_ERR(ac->newtrans)) {
1503		int err = PTR_ERR(ac->newtrans);
1504		kfree(ac);
1505		return err;
1506	}
1507
1508	/* take transaction reference */
1509	cur_trans = trans->transaction;
1510	atomic_inc(&cur_trans->use_count);
1511
1512	btrfs_end_transaction(trans, root);
1513
1514	/*
1515	 * Tell lockdep we've released the freeze rwsem, since the
1516	 * async commit thread will be the one to unlock it.
1517	 */
1518	if (ac->newtrans->type & __TRANS_FREEZABLE)
1519		rwsem_release(
1520			&root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
1521			1, _THIS_IP_);
1522
1523	schedule_work(&ac->work);
1524
1525	/* wait for transaction to start and unblock */
1526	if (wait_for_unblock)
1527		wait_current_trans_commit_start_and_unblock(root, cur_trans);
1528	else
1529		wait_current_trans_commit_start(root, cur_trans);
1530
1531	if (current->journal_info == trans)
1532		current->journal_info = NULL;
1533
1534	btrfs_put_transaction(cur_trans);
1535	return 0;
1536}
1537
1538
1539static void cleanup_transaction(struct btrfs_trans_handle *trans,
1540				struct btrfs_root *root, int err)
1541{
1542	struct btrfs_transaction *cur_trans = trans->transaction;
1543	DEFINE_WAIT(wait);
1544
1545	WARN_ON(trans->use_count > 1);
1546
1547	btrfs_abort_transaction(trans, root, err);
1548
1549	spin_lock(&root->fs_info->trans_lock);
1550
1551	/*
1552	 * If the transaction is removed from the list, it means this
1553	 * transaction has been committed successfully, so it is impossible
1554	 * to call the cleanup function.
1555	 */
1556	BUG_ON(list_empty(&cur_trans->list));
1557
1558	list_del_init(&cur_trans->list);
1559	if (cur_trans == root->fs_info->running_transaction) {
1560		cur_trans->state = TRANS_STATE_COMMIT_DOING;
1561		spin_unlock(&root->fs_info->trans_lock);
1562		wait_event(cur_trans->writer_wait,
1563			   atomic_read(&cur_trans->num_writers) == 1);
1564
1565		spin_lock(&root->fs_info->trans_lock);
1566	}
1567	spin_unlock(&root->fs_info->trans_lock);
1568
1569	btrfs_cleanup_one_transaction(trans->transaction, root);
1570
1571	spin_lock(&root->fs_info->trans_lock);
1572	if (cur_trans == root->fs_info->running_transaction)
1573		root->fs_info->running_transaction = NULL;
1574	spin_unlock(&root->fs_info->trans_lock);
1575
1576	if (trans->type & __TRANS_FREEZABLE)
1577		sb_end_intwrite(root->fs_info->sb);
1578	btrfs_put_transaction(cur_trans);
1579	btrfs_put_transaction(cur_trans);
1580
1581	trace_btrfs_transaction_commit(root);
1582
1583	if (current->journal_info == trans)
1584		current->journal_info = NULL;
1585	btrfs_scrub_cancel(root->fs_info);
1586
1587	kmem_cache_free(btrfs_trans_handle_cachep, trans);
1588}
1589
1590static int btrfs_flush_all_pending_stuffs(struct btrfs_trans_handle *trans,
1591					  struct btrfs_root *root)
1592{
1593	int ret;
1594
1595	ret = btrfs_run_delayed_items(trans, root);
1596	/*
1597	 * running the delayed items may have added new refs. account
1598	 * them now so that they hinder processing of more delayed refs
1599	 * as little as possible.
1600	 */
1601	if (ret) {
1602		btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
1603		return ret;
1604	}
1605
1606	ret = btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
1607	if (ret)
1608		return ret;
1609
1610	/*
1611	 * rename don't use btrfs_join_transaction, so, once we
1612	 * set the transaction to blocked above, we aren't going
1613	 * to get any new ordered operations.  We can safely run
1614	 * it here and no for sure that nothing new will be added
1615	 * to the list
1616	 */
1617	ret = btrfs_run_ordered_operations(trans, root, 1);
1618
1619	return ret;
1620}
1621
1622static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
1623{
1624	if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT))
1625		return btrfs_start_delalloc_roots(fs_info, 1, -1);
1626	return 0;
1627}
1628
1629static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
1630{
1631	if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT))
1632		btrfs_wait_ordered_roots(fs_info, -1);
1633}
1634
 
 
 
 
 
 
 
1635int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1636			     struct btrfs_root *root)
1637{
1638	struct btrfs_transaction *cur_trans = trans->transaction;
1639	struct btrfs_transaction *prev_trans = NULL;
 
1640	int ret;
1641
1642	ret = btrfs_run_ordered_operations(trans, root, 0);
1643	if (ret) {
1644		btrfs_abort_transaction(trans, root, ret);
1645		btrfs_end_transaction(trans, root);
1646		return ret;
1647	}
1648
1649	/* Stop the commit early if ->aborted is set */
1650	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1651		ret = cur_trans->aborted;
1652		btrfs_end_transaction(trans, root);
1653		return ret;
1654	}
1655
1656	/* make a pass through all the delayed refs we have so far
1657	 * any runnings procs may add more while we are here
1658	 */
1659	ret = btrfs_run_delayed_refs(trans, root, 0);
1660	if (ret) {
1661		btrfs_end_transaction(trans, root);
1662		return ret;
1663	}
1664
1665	btrfs_trans_release_metadata(trans, root);
1666	trans->block_rsv = NULL;
1667	if (trans->qgroup_reserved) {
1668		btrfs_qgroup_free(root, trans->qgroup_reserved);
1669		trans->qgroup_reserved = 0;
1670	}
1671
1672	cur_trans = trans->transaction;
1673
1674	/*
1675	 * set the flushing flag so procs in this transaction have to
1676	 * start sending their work down.
1677	 */
1678	cur_trans->delayed_refs.flushing = 1;
1679	smp_wmb();
1680
1681	if (!list_empty(&trans->new_bgs))
1682		btrfs_create_pending_block_groups(trans, root);
1683
1684	ret = btrfs_run_delayed_refs(trans, root, 0);
1685	if (ret) {
1686		btrfs_end_transaction(trans, root);
1687		return ret;
1688	}
1689
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1690	spin_lock(&root->fs_info->trans_lock);
1691	if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
1692		spin_unlock(&root->fs_info->trans_lock);
1693		atomic_inc(&cur_trans->use_count);
1694		ret = btrfs_end_transaction(trans, root);
1695
1696		wait_for_commit(root, cur_trans);
1697
 
 
 
1698		btrfs_put_transaction(cur_trans);
1699
1700		return ret;
1701	}
1702
1703	cur_trans->state = TRANS_STATE_COMMIT_START;
1704	wake_up(&root->fs_info->transaction_blocked_wait);
1705
1706	if (cur_trans->list.prev != &root->fs_info->trans_list) {
1707		prev_trans = list_entry(cur_trans->list.prev,
1708					struct btrfs_transaction, list);
1709		if (prev_trans->state != TRANS_STATE_COMPLETED) {
1710			atomic_inc(&prev_trans->use_count);
1711			spin_unlock(&root->fs_info->trans_lock);
1712
1713			wait_for_commit(root, prev_trans);
 
1714
1715			btrfs_put_transaction(prev_trans);
 
 
1716		} else {
1717			spin_unlock(&root->fs_info->trans_lock);
1718		}
1719	} else {
1720		spin_unlock(&root->fs_info->trans_lock);
1721	}
1722
1723	extwriter_counter_dec(cur_trans, trans->type);
1724
1725	ret = btrfs_start_delalloc_flush(root->fs_info);
1726	if (ret)
1727		goto cleanup_transaction;
1728
1729	ret = btrfs_flush_all_pending_stuffs(trans, root);
1730	if (ret)
1731		goto cleanup_transaction;
1732
1733	wait_event(cur_trans->writer_wait,
1734		   extwriter_counter_read(cur_trans) == 0);
1735
1736	/* some pending stuffs might be added after the previous flush. */
1737	ret = btrfs_flush_all_pending_stuffs(trans, root);
1738	if (ret)
1739		goto cleanup_transaction;
1740
1741	btrfs_wait_delalloc_flush(root->fs_info);
1742
 
 
1743	btrfs_scrub_pause(root);
1744	/*
1745	 * Ok now we need to make sure to block out any other joins while we
1746	 * commit the transaction.  We could have started a join before setting
1747	 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
1748	 */
1749	spin_lock(&root->fs_info->trans_lock);
1750	cur_trans->state = TRANS_STATE_COMMIT_DOING;
1751	spin_unlock(&root->fs_info->trans_lock);
1752	wait_event(cur_trans->writer_wait,
1753		   atomic_read(&cur_trans->num_writers) == 1);
1754
1755	/* ->aborted might be set after the previous check, so check it */
1756	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1757		ret = cur_trans->aborted;
1758		goto scrub_continue;
1759	}
1760	/*
1761	 * the reloc mutex makes sure that we stop
1762	 * the balancing code from coming in and moving
1763	 * extents around in the middle of the commit
1764	 */
1765	mutex_lock(&root->fs_info->reloc_mutex);
1766
1767	/*
1768	 * We needn't worry about the delayed items because we will
1769	 * deal with them in create_pending_snapshot(), which is the
1770	 * core function of the snapshot creation.
1771	 */
1772	ret = create_pending_snapshots(trans, root->fs_info);
1773	if (ret) {
1774		mutex_unlock(&root->fs_info->reloc_mutex);
1775		goto scrub_continue;
1776	}
1777
1778	/*
1779	 * We insert the dir indexes of the snapshots and update the inode
1780	 * of the snapshots' parents after the snapshot creation, so there
1781	 * are some delayed items which are not dealt with. Now deal with
1782	 * them.
1783	 *
1784	 * We needn't worry that this operation will corrupt the snapshots,
1785	 * because all the tree which are snapshoted will be forced to COW
1786	 * the nodes and leaves.
1787	 */
1788	ret = btrfs_run_delayed_items(trans, root);
1789	if (ret) {
1790		mutex_unlock(&root->fs_info->reloc_mutex);
1791		goto scrub_continue;
1792	}
1793
1794	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1795	if (ret) {
1796		mutex_unlock(&root->fs_info->reloc_mutex);
1797		goto scrub_continue;
1798	}
1799
 
 
 
 
 
 
 
1800	/*
1801	 * make sure none of the code above managed to slip in a
1802	 * delayed item
1803	 */
1804	btrfs_assert_delayed_root_empty(root);
1805
1806	WARN_ON(cur_trans != trans->transaction);
1807
1808	/* btrfs_commit_tree_roots is responsible for getting the
1809	 * various roots consistent with each other.  Every pointer
1810	 * in the tree of tree roots has to point to the most up to date
1811	 * root for every subvolume and other tree.  So, we have to keep
1812	 * the tree logging code from jumping in and changing any
1813	 * of the trees.
1814	 *
1815	 * At this point in the commit, there can't be any tree-log
1816	 * writers, but a little lower down we drop the trans mutex
1817	 * and let new people in.  By holding the tree_log_mutex
1818	 * from now until after the super is written, we avoid races
1819	 * with the tree-log code.
1820	 */
1821	mutex_lock(&root->fs_info->tree_log_mutex);
1822
1823	ret = commit_fs_roots(trans, root);
1824	if (ret) {
1825		mutex_unlock(&root->fs_info->tree_log_mutex);
1826		mutex_unlock(&root->fs_info->reloc_mutex);
1827		goto scrub_continue;
1828	}
1829
1830	/*
1831	 * Since the transaction is done, we should set the inode map cache flag
1832	 * before any other comming transaction.
1833	 */
1834	if (btrfs_test_opt(root, CHANGE_INODE_CACHE))
1835		btrfs_set_opt(root->fs_info->mount_opt, INODE_MAP_CACHE);
1836	else
1837		btrfs_clear_opt(root->fs_info->mount_opt, INODE_MAP_CACHE);
1838
1839	/* commit_fs_roots gets rid of all the tree log roots, it is now
1840	 * safe to free the root of tree log roots
1841	 */
1842	btrfs_free_log_root_tree(trans, root->fs_info);
1843
 
 
 
 
 
 
 
 
 
 
 
1844	ret = commit_cowonly_roots(trans, root);
1845	if (ret) {
1846		mutex_unlock(&root->fs_info->tree_log_mutex);
1847		mutex_unlock(&root->fs_info->reloc_mutex);
1848		goto scrub_continue;
1849	}
1850
1851	/*
1852	 * The tasks which save the space cache and inode cache may also
1853	 * update ->aborted, check it.
1854	 */
1855	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1856		ret = cur_trans->aborted;
1857		mutex_unlock(&root->fs_info->tree_log_mutex);
1858		mutex_unlock(&root->fs_info->reloc_mutex);
1859		goto scrub_continue;
1860	}
1861
1862	btrfs_prepare_extent_commit(trans, root);
1863
1864	cur_trans = root->fs_info->running_transaction;
1865
1866	btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1867			    root->fs_info->tree_root->node);
1868	list_add_tail(&root->fs_info->tree_root->dirty_list,
1869		      &cur_trans->switch_commits);
1870
1871	btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1872			    root->fs_info->chunk_root->node);
1873	list_add_tail(&root->fs_info->chunk_root->dirty_list,
1874		      &cur_trans->switch_commits);
1875
1876	switch_commit_roots(cur_trans, root->fs_info);
1877
1878	assert_qgroups_uptodate(trans);
 
 
1879	update_super_roots(root);
1880
1881	btrfs_set_super_log_root(root->fs_info->super_copy, 0);
1882	btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1883	memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
1884	       sizeof(*root->fs_info->super_copy));
1885
 
 
 
 
 
 
 
 
1886	spin_lock(&root->fs_info->trans_lock);
1887	cur_trans->state = TRANS_STATE_UNBLOCKED;
1888	root->fs_info->running_transaction = NULL;
1889	spin_unlock(&root->fs_info->trans_lock);
1890	mutex_unlock(&root->fs_info->reloc_mutex);
1891
1892	wake_up(&root->fs_info->transaction_wait);
1893
1894	ret = btrfs_write_and_wait_transaction(trans, root);
1895	if (ret) {
1896		btrfs_error(root->fs_info, ret,
1897			    "Error while writing out transaction");
1898		mutex_unlock(&root->fs_info->tree_log_mutex);
1899		goto scrub_continue;
1900	}
1901
1902	ret = write_ctree_super(trans, root, 0);
1903	if (ret) {
1904		mutex_unlock(&root->fs_info->tree_log_mutex);
1905		goto scrub_continue;
1906	}
1907
1908	/*
1909	 * the super is written, we can safely allow the tree-loggers
1910	 * to go about their business
1911	 */
1912	mutex_unlock(&root->fs_info->tree_log_mutex);
1913
1914	btrfs_finish_extent_commit(trans, root);
1915
 
 
 
1916	root->fs_info->last_trans_committed = cur_trans->transid;
1917	/*
1918	 * We needn't acquire the lock here because there is no other task
1919	 * which can change it.
1920	 */
1921	cur_trans->state = TRANS_STATE_COMPLETED;
1922	wake_up(&cur_trans->commit_wait);
1923
1924	spin_lock(&root->fs_info->trans_lock);
1925	list_del_init(&cur_trans->list);
1926	spin_unlock(&root->fs_info->trans_lock);
1927
1928	btrfs_put_transaction(cur_trans);
1929	btrfs_put_transaction(cur_trans);
1930
1931	if (trans->type & __TRANS_FREEZABLE)
1932		sb_end_intwrite(root->fs_info->sb);
1933
1934	trace_btrfs_transaction_commit(root);
1935
1936	btrfs_scrub_continue(root);
1937
1938	if (current->journal_info == trans)
1939		current->journal_info = NULL;
1940
1941	kmem_cache_free(btrfs_trans_handle_cachep, trans);
1942
1943	if (current != root->fs_info->transaction_kthread)
 
1944		btrfs_run_delayed_iputs(root);
1945
1946	return ret;
1947
1948scrub_continue:
1949	btrfs_scrub_continue(root);
1950cleanup_transaction:
1951	btrfs_trans_release_metadata(trans, root);
 
1952	trans->block_rsv = NULL;
1953	if (trans->qgroup_reserved) {
1954		btrfs_qgroup_free(root, trans->qgroup_reserved);
1955		trans->qgroup_reserved = 0;
1956	}
1957	btrfs_warn(root->fs_info, "Skipping commit of aborted transaction.");
1958	if (current->journal_info == trans)
1959		current->journal_info = NULL;
1960	cleanup_transaction(trans, root, ret);
1961
1962	return ret;
1963}
1964
1965/*
1966 * return < 0 if error
1967 * 0 if there are no more dead_roots at the time of call
1968 * 1 there are more to be processed, call me again
1969 *
1970 * The return value indicates there are certainly more snapshots to delete, but
1971 * if there comes a new one during processing, it may return 0. We don't mind,
1972 * because btrfs_commit_super will poke cleaner thread and it will process it a
1973 * few seconds later.
1974 */
1975int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
1976{
1977	int ret;
1978	struct btrfs_fs_info *fs_info = root->fs_info;
1979
1980	spin_lock(&fs_info->trans_lock);
1981	if (list_empty(&fs_info->dead_roots)) {
1982		spin_unlock(&fs_info->trans_lock);
1983		return 0;
1984	}
1985	root = list_first_entry(&fs_info->dead_roots,
1986			struct btrfs_root, root_list);
1987	/*
1988	 * Make sure root is not involved in send,
1989	 * if we fail with first root, we return
1990	 * directly rather than continue.
1991	 */
1992	spin_lock(&root->root_item_lock);
1993	if (root->send_in_progress) {
1994		spin_unlock(&fs_info->trans_lock);
1995		spin_unlock(&root->root_item_lock);
1996		return 0;
1997	}
1998	spin_unlock(&root->root_item_lock);
1999
2000	list_del_init(&root->root_list);
2001	spin_unlock(&fs_info->trans_lock);
2002
2003	pr_debug("BTRFS: cleaner removing %llu\n", root->objectid);
2004
2005	btrfs_kill_all_delayed_nodes(root);
2006
2007	if (btrfs_header_backref_rev(root->node) <
2008			BTRFS_MIXED_BACKREF_REV)
2009		ret = btrfs_drop_snapshot(root, NULL, 0, 0);
2010	else
2011		ret = btrfs_drop_snapshot(root, NULL, 1, 0);
2012	/*
2013	 * If we encounter a transaction abort during snapshot cleaning, we
2014	 * don't want to crash here
2015	 */
2016	return (ret < 0) ? 0 : 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2017}