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#include "qgroup.h"
  35
  36#define BTRFS_ROOT_TRANS_TAG 0
  37
  38static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
  39	[TRANS_STATE_RUNNING]		= 0U,
  40	[TRANS_STATE_BLOCKED]		= (__TRANS_USERSPACE |
  41					   __TRANS_START),
  42	[TRANS_STATE_COMMIT_START]	= (__TRANS_USERSPACE |
  43					   __TRANS_START |
  44					   __TRANS_ATTACH),
  45	[TRANS_STATE_COMMIT_DOING]	= (__TRANS_USERSPACE |
  46					   __TRANS_START |
  47					   __TRANS_ATTACH |
  48					   __TRANS_JOIN),
  49	[TRANS_STATE_UNBLOCKED]		= (__TRANS_USERSPACE |
  50					   __TRANS_START |
  51					   __TRANS_ATTACH |
  52					   __TRANS_JOIN |
  53					   __TRANS_JOIN_NOLOCK),
  54	[TRANS_STATE_COMPLETED]		= (__TRANS_USERSPACE |
  55					   __TRANS_START |
  56					   __TRANS_ATTACH |
  57					   __TRANS_JOIN |
  58					   __TRANS_JOIN_NOLOCK),
  59};
  60
  61void btrfs_put_transaction(struct btrfs_transaction *transaction)
  62{
  63	WARN_ON(atomic_read(&transaction->use_count) == 0);
  64	if (atomic_dec_and_test(&transaction->use_count)) {
  65		BUG_ON(!list_empty(&transaction->list));
  66		WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
  67		if (transaction->delayed_refs.pending_csums)
  68			printk(KERN_ERR "pending csums is %llu\n",
  69			       transaction->delayed_refs.pending_csums);
  70		while (!list_empty(&transaction->pending_chunks)) {
  71			struct extent_map *em;
  72
  73			em = list_first_entry(&transaction->pending_chunks,
  74					      struct extent_map, list);
  75			list_del_init(&em->list);
  76			free_extent_map(em);
  77		}
  78		/*
  79		 * If any block groups are found in ->deleted_bgs then it's
  80		 * because the transaction was aborted and a commit did not
  81		 * happen (things failed before writing the new superblock
  82		 * and calling btrfs_finish_extent_commit()), so we can not
  83		 * discard the physical locations of the block groups.
  84		 */
  85		while (!list_empty(&transaction->deleted_bgs)) {
  86			struct btrfs_block_group_cache *cache;
  87
  88			cache = list_first_entry(&transaction->deleted_bgs,
  89						 struct btrfs_block_group_cache,
  90						 bg_list);
  91			list_del_init(&cache->bg_list);
  92			btrfs_put_block_group_trimming(cache);
  93			btrfs_put_block_group(cache);
  94		}
  95		kmem_cache_free(btrfs_transaction_cachep, transaction);
  96	}
  97}
  98
  99static void clear_btree_io_tree(struct extent_io_tree *tree)
 100{
 101	spin_lock(&tree->lock);
 102	/*
 103	 * Do a single barrier for the waitqueue_active check here, the state
 104	 * of the waitqueue should not change once clear_btree_io_tree is
 105	 * called.
 106	 */
 107	smp_mb();
 108	while (!RB_EMPTY_ROOT(&tree->state)) {
 109		struct rb_node *node;
 110		struct extent_state *state;
 111
 112		node = rb_first(&tree->state);
 113		state = rb_entry(node, struct extent_state, rb_node);
 114		rb_erase(&state->rb_node, &tree->state);
 115		RB_CLEAR_NODE(&state->rb_node);
 116		/*
 117		 * btree io trees aren't supposed to have tasks waiting for
 118		 * changes in the flags of extent states ever.
 119		 */
 120		ASSERT(!waitqueue_active(&state->wq));
 121		free_extent_state(state);
 122
 123		cond_resched_lock(&tree->lock);
 124	}
 125	spin_unlock(&tree->lock);
 126}
 127
 128static noinline void switch_commit_roots(struct btrfs_transaction *trans,
 129					 struct btrfs_fs_info *fs_info)
 130{
 131	struct btrfs_root *root, *tmp;
 132
 133	down_write(&fs_info->commit_root_sem);
 134	list_for_each_entry_safe(root, tmp, &trans->switch_commits,
 135				 dirty_list) {
 136		list_del_init(&root->dirty_list);
 137		free_extent_buffer(root->commit_root);
 138		root->commit_root = btrfs_root_node(root);
 139		if (is_fstree(root->objectid))
 140			btrfs_unpin_free_ino(root);
 141		clear_btree_io_tree(&root->dirty_log_pages);
 142	}
 143
 144	/* We can free old roots now. */
 145	spin_lock(&trans->dropped_roots_lock);
 146	while (!list_empty(&trans->dropped_roots)) {
 147		root = list_first_entry(&trans->dropped_roots,
 148					struct btrfs_root, root_list);
 149		list_del_init(&root->root_list);
 150		spin_unlock(&trans->dropped_roots_lock);
 151		btrfs_drop_and_free_fs_root(fs_info, root);
 152		spin_lock(&trans->dropped_roots_lock);
 153	}
 154	spin_unlock(&trans->dropped_roots_lock);
 155	up_write(&fs_info->commit_root_sem);
 156}
 157
 158static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
 159					 unsigned int type)
 160{
 161	if (type & TRANS_EXTWRITERS)
 162		atomic_inc(&trans->num_extwriters);
 163}
 164
 165static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
 166					 unsigned int type)
 167{
 168	if (type & TRANS_EXTWRITERS)
 169		atomic_dec(&trans->num_extwriters);
 170}
 171
 172static inline void extwriter_counter_init(struct btrfs_transaction *trans,
 173					  unsigned int type)
 174{
 175	atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
 176}
 177
 178static inline int extwriter_counter_read(struct btrfs_transaction *trans)
 179{
 180	return atomic_read(&trans->num_extwriters);
 181}
 182
 183/*
 184 * either allocate a new transaction or hop into the existing one
 185 */
 186static noinline int join_transaction(struct btrfs_root *root, unsigned int type)
 187{
 188	struct btrfs_transaction *cur_trans;
 189	struct btrfs_fs_info *fs_info = root->fs_info;
 190
 191	spin_lock(&fs_info->trans_lock);
 192loop:
 193	/* The file system has been taken offline. No new transactions. */
 194	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 195		spin_unlock(&fs_info->trans_lock);
 196		return -EROFS;
 197	}
 198
 
 
 
 
 
 
 
 199	cur_trans = fs_info->running_transaction;
 200	if (cur_trans) {
 201		if (cur_trans->aborted) {
 202			spin_unlock(&fs_info->trans_lock);
 203			return cur_trans->aborted;
 204		}
 205		if (btrfs_blocked_trans_types[cur_trans->state] & type) {
 206			spin_unlock(&fs_info->trans_lock);
 207			return -EBUSY;
 208		}
 209		atomic_inc(&cur_trans->use_count);
 210		atomic_inc(&cur_trans->num_writers);
 211		extwriter_counter_inc(cur_trans, type);
 212		spin_unlock(&fs_info->trans_lock);
 213		return 0;
 214	}
 215	spin_unlock(&fs_info->trans_lock);
 216
 217	/*
 218	 * If we are ATTACH, we just want to catch the current transaction,
 219	 * and commit it. If there is no transaction, just return ENOENT.
 220	 */
 221	if (type == TRANS_ATTACH)
 222		return -ENOENT;
 223
 224	/*
 225	 * JOIN_NOLOCK only happens during the transaction commit, so
 226	 * it is impossible that ->running_transaction is NULL
 227	 */
 228	BUG_ON(type == TRANS_JOIN_NOLOCK);
 229
 230	cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
 231	if (!cur_trans)
 232		return -ENOMEM;
 233
 234	spin_lock(&fs_info->trans_lock);
 235	if (fs_info->running_transaction) {
 236		/*
 237		 * someone started a transaction after we unlocked.  Make sure
 238		 * to redo the checks above
 239		 */
 240		kmem_cache_free(btrfs_transaction_cachep, cur_trans);
 
 241		goto loop;
 242	} else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 243		spin_unlock(&fs_info->trans_lock);
 244		kmem_cache_free(btrfs_transaction_cachep, cur_trans);
 245		return -EROFS;
 246	}
 247
 248	atomic_set(&cur_trans->num_writers, 1);
 249	extwriter_counter_init(cur_trans, type);
 250	init_waitqueue_head(&cur_trans->writer_wait);
 251	init_waitqueue_head(&cur_trans->commit_wait);
 252	init_waitqueue_head(&cur_trans->pending_wait);
 253	cur_trans->state = TRANS_STATE_RUNNING;
 254	/*
 255	 * One for this trans handle, one so it will live on until we
 256	 * commit the transaction.
 257	 */
 258	atomic_set(&cur_trans->use_count, 2);
 259	atomic_set(&cur_trans->pending_ordered, 0);
 260	cur_trans->flags = 0;
 261	cur_trans->start_time = get_seconds();
 262
 263	memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
 264
 265	cur_trans->delayed_refs.href_root = RB_ROOT;
 266	cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
 267	atomic_set(&cur_trans->delayed_refs.num_entries, 0);
 
 
 268
 269	/*
 270	 * although the tree mod log is per file system and not per transaction,
 271	 * the log must never go across transaction boundaries.
 272	 */
 273	smp_mb();
 274	if (!list_empty(&fs_info->tree_mod_seq_list))
 275		WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when "
 276			"creating a fresh transaction\n");
 277	if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
 278		WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when "
 
 
 279			"creating a fresh transaction\n");
 280	atomic64_set(&fs_info->tree_mod_seq, 0);
 
 
 281
 
 
 282	spin_lock_init(&cur_trans->delayed_refs.lock);
 
 283
 284	INIT_LIST_HEAD(&cur_trans->pending_snapshots);
 285	INIT_LIST_HEAD(&cur_trans->pending_chunks);
 286	INIT_LIST_HEAD(&cur_trans->switch_commits);
 287	INIT_LIST_HEAD(&cur_trans->dirty_bgs);
 288	INIT_LIST_HEAD(&cur_trans->io_bgs);
 289	INIT_LIST_HEAD(&cur_trans->dropped_roots);
 290	mutex_init(&cur_trans->cache_write_mutex);
 291	cur_trans->num_dirty_bgs = 0;
 292	spin_lock_init(&cur_trans->dirty_bgs_lock);
 293	INIT_LIST_HEAD(&cur_trans->deleted_bgs);
 294	spin_lock_init(&cur_trans->dropped_roots_lock);
 295	list_add_tail(&cur_trans->list, &fs_info->trans_list);
 296	extent_io_tree_init(&cur_trans->dirty_pages,
 297			     fs_info->btree_inode->i_mapping);
 298	fs_info->generation++;
 299	cur_trans->transid = fs_info->generation;
 300	fs_info->running_transaction = cur_trans;
 301	cur_trans->aborted = 0;
 302	spin_unlock(&fs_info->trans_lock);
 303
 304	return 0;
 305}
 306
 307/*
 308 * this does all the record keeping required to make sure that a reference
 309 * counted root is properly recorded in a given transaction.  This is required
 310 * to make sure the old root from before we joined the transaction is deleted
 311 * when the transaction commits
 312 */
 313static int record_root_in_trans(struct btrfs_trans_handle *trans,
 314			       struct btrfs_root *root)
 315{
 316	if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
 317	    root->last_trans < trans->transid) {
 318		WARN_ON(root == root->fs_info->extent_root);
 319		WARN_ON(root->commit_root != root->node);
 320
 321		/*
 322		 * see below for IN_TRANS_SETUP usage rules
 323		 * we have the reloc mutex held now, so there
 324		 * is only one writer in this function
 325		 */
 326		set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
 327
 328		/* make sure readers find IN_TRANS_SETUP before
 329		 * they find our root->last_trans update
 330		 */
 331		smp_wmb();
 332
 333		spin_lock(&root->fs_info->fs_roots_radix_lock);
 334		if (root->last_trans == trans->transid) {
 335			spin_unlock(&root->fs_info->fs_roots_radix_lock);
 336			return 0;
 337		}
 338		radix_tree_tag_set(&root->fs_info->fs_roots_radix,
 339			   (unsigned long)root->root_key.objectid,
 340			   BTRFS_ROOT_TRANS_TAG);
 341		spin_unlock(&root->fs_info->fs_roots_radix_lock);
 342		root->last_trans = trans->transid;
 343
 344		/* this is pretty tricky.  We don't want to
 345		 * take the relocation lock in btrfs_record_root_in_trans
 346		 * unless we're really doing the first setup for this root in
 347		 * this transaction.
 348		 *
 349		 * Normally we'd use root->last_trans as a flag to decide
 350		 * if we want to take the expensive mutex.
 351		 *
 352		 * But, we have to set root->last_trans before we
 353		 * init the relocation root, otherwise, we trip over warnings
 354		 * in ctree.c.  The solution used here is to flag ourselves
 355		 * with root IN_TRANS_SETUP.  When this is 1, we're still
 356		 * fixing up the reloc trees and everyone must wait.
 357		 *
 358		 * When this is zero, they can trust root->last_trans and fly
 359		 * through btrfs_record_root_in_trans without having to take the
 360		 * lock.  smp_wmb() makes sure that all the writes above are
 361		 * done before we pop in the zero below
 362		 */
 363		btrfs_init_reloc_root(trans, root);
 364		smp_mb__before_atomic();
 365		clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
 366	}
 367	return 0;
 368}
 369
 370
 371void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
 372			    struct btrfs_root *root)
 373{
 374	struct btrfs_transaction *cur_trans = trans->transaction;
 375
 376	/* Add ourselves to the transaction dropped list */
 377	spin_lock(&cur_trans->dropped_roots_lock);
 378	list_add_tail(&root->root_list, &cur_trans->dropped_roots);
 379	spin_unlock(&cur_trans->dropped_roots_lock);
 380
 381	/* Make sure we don't try to update the root at commit time */
 382	spin_lock(&root->fs_info->fs_roots_radix_lock);
 383	radix_tree_tag_clear(&root->fs_info->fs_roots_radix,
 384			     (unsigned long)root->root_key.objectid,
 385			     BTRFS_ROOT_TRANS_TAG);
 386	spin_unlock(&root->fs_info->fs_roots_radix_lock);
 387}
 388
 389int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
 390			       struct btrfs_root *root)
 391{
 392	if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
 393		return 0;
 394
 395	/*
 396	 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
 397	 * and barriers
 398	 */
 399	smp_rmb();
 400	if (root->last_trans == trans->transid &&
 401	    !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
 402		return 0;
 403
 404	mutex_lock(&root->fs_info->reloc_mutex);
 405	record_root_in_trans(trans, root);
 406	mutex_unlock(&root->fs_info->reloc_mutex);
 407
 408	return 0;
 409}
 410
 411static inline int is_transaction_blocked(struct btrfs_transaction *trans)
 412{
 413	return (trans->state >= TRANS_STATE_BLOCKED &&
 414		trans->state < TRANS_STATE_UNBLOCKED &&
 415		!trans->aborted);
 416}
 417
 418/* wait for commit against the current transaction to become unblocked
 419 * when this is done, it is safe to start a new transaction, but the current
 420 * transaction might not be fully on disk.
 421 */
 422static void wait_current_trans(struct btrfs_root *root)
 423{
 424	struct btrfs_transaction *cur_trans;
 425
 426	spin_lock(&root->fs_info->trans_lock);
 427	cur_trans = root->fs_info->running_transaction;
 428	if (cur_trans && is_transaction_blocked(cur_trans)) {
 429		atomic_inc(&cur_trans->use_count);
 430		spin_unlock(&root->fs_info->trans_lock);
 431
 432		wait_event(root->fs_info->transaction_wait,
 433			   cur_trans->state >= TRANS_STATE_UNBLOCKED ||
 434			   cur_trans->aborted);
 435		btrfs_put_transaction(cur_trans);
 436	} else {
 437		spin_unlock(&root->fs_info->trans_lock);
 438	}
 439}
 440
 
 
 
 
 
 
 
 441static int may_wait_transaction(struct btrfs_root *root, int type)
 442{
 443	if (root->fs_info->log_root_recovering)
 444		return 0;
 445
 446	if (type == TRANS_USERSPACE)
 447		return 1;
 448
 449	if (type == TRANS_START &&
 450	    !atomic_read(&root->fs_info->open_ioctl_trans))
 451		return 1;
 452
 453	return 0;
 454}
 455
 456static inline bool need_reserve_reloc_root(struct btrfs_root *root)
 457{
 458	if (!root->fs_info->reloc_ctl ||
 459	    !test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
 460	    root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
 461	    root->reloc_root)
 462		return false;
 463
 464	return true;
 465}
 466
 467static struct btrfs_trans_handle *
 468start_transaction(struct btrfs_root *root, unsigned int num_items,
 469		  unsigned int type, enum btrfs_reserve_flush_enum flush)
 470{
 471	struct btrfs_trans_handle *h;
 472	struct btrfs_transaction *cur_trans;
 473	u64 num_bytes = 0;
 474	u64 qgroup_reserved = 0;
 475	bool reloc_reserved = false;
 476	int ret;
 477
 478	/* Send isn't supposed to start transactions. */
 479	ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB);
 480
 481	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
 482		return ERR_PTR(-EROFS);
 483
 484	if (current->journal_info) {
 485		WARN_ON(type & TRANS_EXTWRITERS);
 486		h = current->journal_info;
 487		h->use_count++;
 488		WARN_ON(h->use_count > 2);
 489		h->orig_rsv = h->block_rsv;
 490		h->block_rsv = NULL;
 491		goto got_it;
 492	}
 493
 494	/*
 495	 * Do the reservation before we join the transaction so we can do all
 496	 * the appropriate flushing if need be.
 497	 */
 498	if (num_items > 0 && root != root->fs_info->chunk_root) {
 499		qgroup_reserved = num_items * root->nodesize;
 500		ret = btrfs_qgroup_reserve_meta(root, qgroup_reserved);
 501		if (ret)
 502			return ERR_PTR(ret);
 503
 504		num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
 505		/*
 506		 * Do the reservation for the relocation root creation
 507		 */
 508		if (need_reserve_reloc_root(root)) {
 509			num_bytes += root->nodesize;
 510			reloc_reserved = true;
 511		}
 512
 513		ret = btrfs_block_rsv_add(root,
 514					  &root->fs_info->trans_block_rsv,
 515					  num_bytes, flush);
 516		if (ret)
 517			goto reserve_fail;
 518	}
 519again:
 520	h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
 521	if (!h) {
 522		ret = -ENOMEM;
 523		goto alloc_fail;
 524	}
 525
 526	/*
 527	 * If we are JOIN_NOLOCK we're already committing a transaction and
 528	 * waiting on this guy, so we don't need to do the sb_start_intwrite
 529	 * because we're already holding a ref.  We need this because we could
 530	 * have raced in and did an fsync() on a file which can kick a commit
 531	 * and then we deadlock with somebody doing a freeze.
 532	 *
 533	 * If we are ATTACH, it means we just want to catch the current
 534	 * transaction and commit it, so we needn't do sb_start_intwrite(). 
 535	 */
 536	if (type & __TRANS_FREEZABLE)
 537		sb_start_intwrite(root->fs_info->sb);
 538
 539	if (may_wait_transaction(root, type))
 540		wait_current_trans(root);
 541
 542	do {
 543		ret = join_transaction(root, type);
 544		if (ret == -EBUSY) {
 545			wait_current_trans(root);
 546			if (unlikely(type == TRANS_ATTACH))
 547				ret = -ENOENT;
 548		}
 549	} while (ret == -EBUSY);
 550
 551	if (ret < 0) {
 552		/* We must get the transaction if we are JOIN_NOLOCK. */
 553		BUG_ON(type == TRANS_JOIN_NOLOCK);
 554		goto join_fail;
 555	}
 556
 557	cur_trans = root->fs_info->running_transaction;
 558
 559	h->transid = cur_trans->transid;
 560	h->transaction = cur_trans;
 561	h->root = root;
 
 
 562	h->use_count = 1;
 563
 564	h->type = type;
 565	h->can_flush_pending_bgs = true;
 566	INIT_LIST_HEAD(&h->qgroup_ref_list);
 567	INIT_LIST_HEAD(&h->new_bgs);
 568
 569	smp_mb();
 570	if (cur_trans->state >= TRANS_STATE_BLOCKED &&
 571	    may_wait_transaction(root, type)) {
 572		current->journal_info = h;
 573		btrfs_commit_transaction(h, root);
 574		goto again;
 575	}
 576
 577	if (num_bytes) {
 578		trace_btrfs_space_reservation(root->fs_info, "transaction",
 579					      h->transid, num_bytes, 1);
 580		h->block_rsv = &root->fs_info->trans_block_rsv;
 581		h->bytes_reserved = num_bytes;
 582		h->reloc_reserved = reloc_reserved;
 583	}
 584
 585got_it:
 586	btrfs_record_root_in_trans(h, root);
 587
 588	if (!current->journal_info && type != TRANS_USERSPACE)
 589		current->journal_info = h;
 590	return h;
 591
 592join_fail:
 593	if (type & __TRANS_FREEZABLE)
 594		sb_end_intwrite(root->fs_info->sb);
 595	kmem_cache_free(btrfs_trans_handle_cachep, h);
 596alloc_fail:
 597	if (num_bytes)
 598		btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv,
 599					num_bytes);
 600reserve_fail:
 601	btrfs_qgroup_free_meta(root, qgroup_reserved);
 602	return ERR_PTR(ret);
 603}
 604
 605struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 606						   unsigned int num_items)
 607{
 608	return start_transaction(root, num_items, TRANS_START,
 609				 BTRFS_RESERVE_FLUSH_ALL);
 610}
 611struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
 612					struct btrfs_root *root,
 613					unsigned int num_items,
 614					int min_factor)
 615{
 616	struct btrfs_trans_handle *trans;
 617	u64 num_bytes;
 618	int ret;
 619
 620	trans = btrfs_start_transaction(root, num_items);
 621	if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
 622		return trans;
 623
 624	trans = btrfs_start_transaction(root, 0);
 625	if (IS_ERR(trans))
 626		return trans;
 627
 628	num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
 629	ret = btrfs_cond_migrate_bytes(root->fs_info,
 630				       &root->fs_info->trans_block_rsv,
 631				       num_bytes,
 632				       min_factor);
 633	if (ret) {
 634		btrfs_end_transaction(trans, root);
 635		return ERR_PTR(ret);
 636	}
 637
 638	trans->block_rsv = &root->fs_info->trans_block_rsv;
 639	trans->bytes_reserved = num_bytes;
 640	trace_btrfs_space_reservation(root->fs_info, "transaction",
 641				      trans->transid, num_bytes, 1);
 642
 643	return trans;
 644}
 645
 646struct btrfs_trans_handle *btrfs_start_transaction_lflush(
 647					struct btrfs_root *root,
 648					unsigned int num_items)
 649{
 650	return start_transaction(root, num_items, TRANS_START,
 651				 BTRFS_RESERVE_FLUSH_LIMIT);
 652}
 653
 654struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
 655{
 656	return start_transaction(root, 0, TRANS_JOIN,
 657				 BTRFS_RESERVE_NO_FLUSH);
 658}
 659
 660struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
 661{
 662	return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
 663				 BTRFS_RESERVE_NO_FLUSH);
 664}
 665
 666struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
 667{
 668	return start_transaction(root, 0, TRANS_USERSPACE,
 669				 BTRFS_RESERVE_NO_FLUSH);
 670}
 671
 672/*
 673 * btrfs_attach_transaction() - catch the running transaction
 674 *
 675 * It is used when we want to commit the current the transaction, but
 676 * don't want to start a new one.
 677 *
 678 * Note: If this function return -ENOENT, it just means there is no
 679 * running transaction. But it is possible that the inactive transaction
 680 * is still in the memory, not fully on disk. If you hope there is no
 681 * inactive transaction in the fs when -ENOENT is returned, you should
 682 * invoke
 683 *     btrfs_attach_transaction_barrier()
 684 */
 685struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
 686{
 687	return start_transaction(root, 0, TRANS_ATTACH,
 688				 BTRFS_RESERVE_NO_FLUSH);
 689}
 690
 691/*
 692 * btrfs_attach_transaction_barrier() - catch the running transaction
 693 *
 694 * It is similar to the above function, the differentia is this one
 695 * will wait for all the inactive transactions until they fully
 696 * complete.
 697 */
 698struct btrfs_trans_handle *
 699btrfs_attach_transaction_barrier(struct btrfs_root *root)
 700{
 701	struct btrfs_trans_handle *trans;
 702
 703	trans = start_transaction(root, 0, TRANS_ATTACH,
 704				  BTRFS_RESERVE_NO_FLUSH);
 705	if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT)
 706		btrfs_wait_for_commit(root, 0);
 707
 708	return trans;
 709}
 710
 711/* wait for a transaction commit to be fully complete */
 712static noinline void wait_for_commit(struct btrfs_root *root,
 713				    struct btrfs_transaction *commit)
 714{
 715	wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED);
 716}
 717
 718int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
 719{
 720	struct btrfs_transaction *cur_trans = NULL, *t;
 721	int ret = 0;
 722
 
 723	if (transid) {
 724		if (transid <= root->fs_info->last_trans_committed)
 725			goto out;
 726
 727		/* find specified transaction */
 728		spin_lock(&root->fs_info->trans_lock);
 729		list_for_each_entry(t, &root->fs_info->trans_list, list) {
 730			if (t->transid == transid) {
 731				cur_trans = t;
 732				atomic_inc(&cur_trans->use_count);
 733				ret = 0;
 734				break;
 735			}
 736			if (t->transid > transid) {
 737				ret = 0;
 738				break;
 739			}
 740		}
 741		spin_unlock(&root->fs_info->trans_lock);
 742
 743		/*
 744		 * The specified transaction doesn't exist, or we
 745		 * raced with btrfs_commit_transaction
 746		 */
 747		if (!cur_trans) {
 748			if (transid > root->fs_info->last_trans_committed)
 749				ret = -EINVAL;
 750			goto out;
 751		}
 752	} else {
 753		/* find newest transaction that is committing | committed */
 754		spin_lock(&root->fs_info->trans_lock);
 755		list_for_each_entry_reverse(t, &root->fs_info->trans_list,
 756					    list) {
 757			if (t->state >= TRANS_STATE_COMMIT_START) {
 758				if (t->state == TRANS_STATE_COMPLETED)
 759					break;
 760				cur_trans = t;
 761				atomic_inc(&cur_trans->use_count);
 762				break;
 763			}
 764		}
 765		spin_unlock(&root->fs_info->trans_lock);
 766		if (!cur_trans)
 767			goto out;  /* nothing committing|committed */
 768	}
 769
 770	wait_for_commit(root, cur_trans);
 771	btrfs_put_transaction(cur_trans);
 
 
 772out:
 773	return ret;
 774}
 775
 776void btrfs_throttle(struct btrfs_root *root)
 777{
 778	if (!atomic_read(&root->fs_info->open_ioctl_trans))
 779		wait_current_trans(root);
 780}
 781
 782static int should_end_transaction(struct btrfs_trans_handle *trans,
 783				  struct btrfs_root *root)
 784{
 785	if (root->fs_info->global_block_rsv.space_info->full &&
 786	    btrfs_check_space_for_delayed_refs(trans, root))
 787		return 1;
 788
 789	return !!btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
 
 790}
 791
 792int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
 793				 struct btrfs_root *root)
 794{
 795	struct btrfs_transaction *cur_trans = trans->transaction;
 
 796	int updates;
 797	int err;
 798
 799	smp_mb();
 800	if (cur_trans->state >= TRANS_STATE_BLOCKED ||
 801	    cur_trans->delayed_refs.flushing)
 802		return 1;
 803
 
 
 
 
 
 
 804	updates = trans->delayed_ref_updates;
 805	trans->delayed_ref_updates = 0;
 806	if (updates) {
 807		err = btrfs_run_delayed_refs(trans, root, updates * 2);
 808		if (err) /* Error code will also eval true */
 809			return err;
 810	}
 811
 
 
 812	return should_end_transaction(trans, root);
 813}
 814
 815static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 816			  struct btrfs_root *root, int throttle)
 817{
 818	struct btrfs_transaction *cur_trans = trans->transaction;
 819	struct btrfs_fs_info *info = root->fs_info;
 820	unsigned long cur = trans->delayed_ref_updates;
 821	int lock = (trans->type != TRANS_JOIN_NOLOCK);
 822	int err = 0;
 823	int must_run_delayed_refs = 0;
 824
 825	if (trans->use_count > 1) {
 826		trans->use_count--;
 827		trans->block_rsv = trans->orig_rsv;
 828		return 0;
 829	}
 830
 831	btrfs_trans_release_metadata(trans, root);
 832	trans->block_rsv = NULL;
 833
 834	if (!list_empty(&trans->new_bgs))
 835		btrfs_create_pending_block_groups(trans, root);
 836
 837	trans->delayed_ref_updates = 0;
 838	if (!trans->sync) {
 839		must_run_delayed_refs =
 840			btrfs_should_throttle_delayed_refs(trans, root);
 841		cur = max_t(unsigned long, cur, 32);
 842
 843		/*
 844		 * don't make the caller wait if they are from a NOLOCK
 845		 * or ATTACH transaction, it will deadlock with commit
 846		 */
 847		if (must_run_delayed_refs == 1 &&
 848		    (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH)))
 849			must_run_delayed_refs = 2;
 850	}
 851
 852	btrfs_trans_release_metadata(trans, root);
 853	trans->block_rsv = NULL;
 854
 855	if (!list_empty(&trans->new_bgs))
 856		btrfs_create_pending_block_groups(trans, root);
 857
 858	btrfs_trans_release_chunk_metadata(trans);
 859
 860	if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
 861	    should_end_transaction(trans, root) &&
 862	    ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) {
 863		spin_lock(&info->trans_lock);
 864		if (cur_trans->state == TRANS_STATE_RUNNING)
 865			cur_trans->state = TRANS_STATE_BLOCKED;
 866		spin_unlock(&info->trans_lock);
 867	}
 868
 869	if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
 870		if (throttle)
 
 
 
 
 
 
 871			return btrfs_commit_transaction(trans, root);
 872		else
 873			wake_up_process(info->transaction_kthread);
 
 874	}
 875
 876	if (trans->type & __TRANS_FREEZABLE)
 877		sb_end_intwrite(root->fs_info->sb);
 878
 879	WARN_ON(cur_trans != info->running_transaction);
 880	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
 881	atomic_dec(&cur_trans->num_writers);
 882	extwriter_counter_dec(cur_trans, trans->type);
 883
 884	/*
 885	 * Make sure counter is updated before we wake up waiters.
 886	 */
 887	smp_mb();
 888	if (waitqueue_active(&cur_trans->writer_wait))
 889		wake_up(&cur_trans->writer_wait);
 890	btrfs_put_transaction(cur_trans);
 891
 892	if (current->journal_info == trans)
 893		current->journal_info = NULL;
 894
 895	if (throttle)
 896		btrfs_run_delayed_iputs(root);
 897
 898	if (trans->aborted ||
 899	    test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
 900		wake_up_process(info->transaction_kthread);
 901		err = -EIO;
 902	}
 903	assert_qgroups_uptodate(trans);
 904
 
 905	kmem_cache_free(btrfs_trans_handle_cachep, trans);
 906	if (must_run_delayed_refs) {
 907		btrfs_async_run_delayed_refs(root, cur,
 908					     must_run_delayed_refs == 1);
 909	}
 910	return err;
 911}
 912
 913int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 914			  struct btrfs_root *root)
 915{
 916	return __btrfs_end_transaction(trans, root, 0);
 
 
 
 
 
 917}
 918
 919int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
 920				   struct btrfs_root *root)
 921{
 922	return __btrfs_end_transaction(trans, root, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 923}
 924
 925/*
 926 * when btree blocks are allocated, they have some corresponding bits set for
 927 * them in one of two extent_io trees.  This is used to make sure all of
 928 * those extents are sent to disk but does not wait on them
 929 */
 930int btrfs_write_marked_extents(struct btrfs_root *root,
 931			       struct extent_io_tree *dirty_pages, int mark)
 932{
 933	int err = 0;
 934	int werr = 0;
 935	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 936	struct extent_state *cached_state = NULL;
 937	u64 start = 0;
 938	u64 end;
 939
 940	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
 941				      mark, &cached_state)) {
 942		bool wait_writeback = false;
 943
 944		err = convert_extent_bit(dirty_pages, start, end,
 945					 EXTENT_NEED_WAIT,
 946					 mark, &cached_state, GFP_NOFS);
 947		/*
 948		 * convert_extent_bit can return -ENOMEM, which is most of the
 949		 * time a temporary error. So when it happens, ignore the error
 950		 * and wait for writeback of this range to finish - because we
 951		 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
 952		 * to btrfs_wait_marked_extents() would not know that writeback
 953		 * for this range started and therefore wouldn't wait for it to
 954		 * finish - we don't want to commit a superblock that points to
 955		 * btree nodes/leafs for which writeback hasn't finished yet
 956		 * (and without errors).
 957		 * We cleanup any entries left in the io tree when committing
 958		 * the transaction (through clear_btree_io_tree()).
 959		 */
 960		if (err == -ENOMEM) {
 961			err = 0;
 962			wait_writeback = true;
 963		}
 964		if (!err)
 965			err = filemap_fdatawrite_range(mapping, start, end);
 966		if (err)
 967			werr = err;
 968		else if (wait_writeback)
 969			werr = filemap_fdatawait_range(mapping, start, end);
 970		free_extent_state(cached_state);
 971		cached_state = NULL;
 972		cond_resched();
 973		start = end + 1;
 974	}
 
 
 975	return werr;
 976}
 977
 978/*
 979 * when btree blocks are allocated, they have some corresponding bits set for
 980 * them in one of two extent_io trees.  This is used to make sure all of
 981 * those extents are on disk for transaction or log commit.  We wait
 982 * on all the pages and clear them from the dirty pages state tree
 983 */
 984int btrfs_wait_marked_extents(struct btrfs_root *root,
 985			      struct extent_io_tree *dirty_pages, int mark)
 986{
 987	int err = 0;
 988	int werr = 0;
 989	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 990	struct extent_state *cached_state = NULL;
 991	u64 start = 0;
 992	u64 end;
 993	struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode);
 994	bool errors = false;
 995
 996	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
 997				      EXTENT_NEED_WAIT, &cached_state)) {
 998		/*
 999		 * Ignore -ENOMEM errors returned by clear_extent_bit().
1000		 * When committing the transaction, we'll remove any entries
1001		 * left in the io tree. For a log commit, we don't remove them
1002		 * after committing the log because the tree can be accessed
1003		 * concurrently - we do it only at transaction commit time when
1004		 * it's safe to do it (through clear_btree_io_tree()).
1005		 */
1006		err = clear_extent_bit(dirty_pages, start, end,
1007				       EXTENT_NEED_WAIT,
1008				       0, 0, &cached_state, GFP_NOFS);
1009		if (err == -ENOMEM)
1010			err = 0;
1011		if (!err)
1012			err = filemap_fdatawait_range(mapping, start, end);
1013		if (err)
1014			werr = err;
1015		free_extent_state(cached_state);
1016		cached_state = NULL;
1017		cond_resched();
1018		start = end + 1;
1019	}
1020	if (err)
1021		werr = err;
1022
1023	if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
1024		if ((mark & EXTENT_DIRTY) &&
1025		    test_and_clear_bit(BTRFS_INODE_BTREE_LOG1_ERR,
1026				       &btree_ino->runtime_flags))
1027			errors = true;
1028
1029		if ((mark & EXTENT_NEW) &&
1030		    test_and_clear_bit(BTRFS_INODE_BTREE_LOG2_ERR,
1031				       &btree_ino->runtime_flags))
1032			errors = true;
1033	} else {
1034		if (test_and_clear_bit(BTRFS_INODE_BTREE_ERR,
1035				       &btree_ino->runtime_flags))
1036			errors = true;
1037	}
1038
1039	if (errors && !werr)
1040		werr = -EIO;
1041
1042	return werr;
1043}
1044
1045/*
1046 * when btree blocks are allocated, they have some corresponding bits set for
1047 * them in one of two extent_io trees.  This is used to make sure all of
1048 * those extents are on disk for transaction or log commit
1049 */
1050static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
1051				struct extent_io_tree *dirty_pages, int mark)
1052{
1053	int ret;
1054	int ret2;
1055	struct blk_plug plug;
1056
1057	blk_start_plug(&plug);
1058	ret = btrfs_write_marked_extents(root, dirty_pages, mark);
1059	blk_finish_plug(&plug);
1060	ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
1061
1062	if (ret)
1063		return ret;
1064	if (ret2)
1065		return ret2;
1066	return 0;
1067}
1068
1069static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
1070				     struct btrfs_root *root)
1071{
1072	int ret;
1073
1074	ret = btrfs_write_and_wait_marked_extents(root,
 
 
 
1075					   &trans->transaction->dirty_pages,
1076					   EXTENT_DIRTY);
1077	clear_btree_io_tree(&trans->transaction->dirty_pages);
1078
1079	return ret;
1080}
1081
1082/*
1083 * this is used to update the root pointer in the tree of tree roots.
1084 *
1085 * But, in the case of the extent allocation tree, updating the root
1086 * pointer may allocate blocks which may change the root of the extent
1087 * allocation tree.
1088 *
1089 * So, this loops and repeats and makes sure the cowonly root didn't
1090 * change while the root pointer was being updated in the metadata.
1091 */
1092static int update_cowonly_root(struct btrfs_trans_handle *trans,
1093			       struct btrfs_root *root)
1094{
1095	int ret;
1096	u64 old_root_bytenr;
1097	u64 old_root_used;
1098	struct btrfs_root *tree_root = root->fs_info->tree_root;
1099
1100	old_root_used = btrfs_root_used(&root->root_item);
 
1101
1102	while (1) {
1103		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1104		if (old_root_bytenr == root->node->start &&
1105		    old_root_used == btrfs_root_used(&root->root_item))
1106			break;
1107
1108		btrfs_set_root_node(&root->root_item, root->node);
1109		ret = btrfs_update_root(trans, tree_root,
1110					&root->root_key,
1111					&root->root_item);
1112		if (ret)
1113			return ret;
1114
1115		old_root_used = btrfs_root_used(&root->root_item);
 
 
 
1116	}
1117
 
 
 
1118	return 0;
1119}
1120
1121/*
1122 * update all the cowonly tree roots on disk
1123 *
1124 * The error handling in this function may not be obvious. Any of the
1125 * failures will cause the file system to go offline. We still need
1126 * to clean up the delayed refs.
1127 */
1128static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
1129					 struct btrfs_root *root)
1130{
1131	struct btrfs_fs_info *fs_info = root->fs_info;
1132	struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1133	struct list_head *io_bgs = &trans->transaction->io_bgs;
1134	struct list_head *next;
1135	struct extent_buffer *eb;
1136	int ret;
1137
 
 
 
 
1138	eb = btrfs_lock_root_node(fs_info->tree_root);
1139	ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1140			      0, &eb);
1141	btrfs_tree_unlock(eb);
1142	free_extent_buffer(eb);
1143
1144	if (ret)
1145		return ret;
1146
1147	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1148	if (ret)
1149		return ret;
1150
1151	ret = btrfs_run_dev_stats(trans, root->fs_info);
1152	if (ret)
1153		return ret;
1154	ret = btrfs_run_dev_replace(trans, root->fs_info);
1155	if (ret)
1156		return ret;
1157	ret = btrfs_run_qgroups(trans, root->fs_info);
1158	if (ret)
1159		return ret;
1160
1161	ret = btrfs_setup_space_cache(trans, root);
1162	if (ret)
1163		return ret;
1164
1165	/* run_qgroups might have added some more refs */
1166	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1167	if (ret)
1168		return ret;
1169again:
1170	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1171		next = fs_info->dirty_cowonly_roots.next;
1172		list_del_init(next);
1173		root = list_entry(next, struct btrfs_root, dirty_list);
1174		clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1175
1176		if (root != fs_info->extent_root)
1177			list_add_tail(&root->dirty_list,
1178				      &trans->transaction->switch_commits);
1179		ret = update_cowonly_root(trans, root);
1180		if (ret)
1181			return ret;
1182		ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1183		if (ret)
1184			return ret;
1185	}
1186
1187	while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1188		ret = btrfs_write_dirty_block_groups(trans, root);
1189		if (ret)
1190			return ret;
1191		ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1192		if (ret)
1193			return ret;
1194	}
1195
1196	if (!list_empty(&fs_info->dirty_cowonly_roots))
1197		goto again;
1198
1199	list_add_tail(&fs_info->extent_root->dirty_list,
1200		      &trans->transaction->switch_commits);
1201	btrfs_after_dev_replace_commit(fs_info);
1202
1203	return 0;
1204}
1205
1206/*
1207 * dead roots are old snapshots that need to be deleted.  This allocates
1208 * a dirty root struct and adds it into the list of dead roots that need to
1209 * be deleted
1210 */
1211void btrfs_add_dead_root(struct btrfs_root *root)
1212{
1213	spin_lock(&root->fs_info->trans_lock);
1214	if (list_empty(&root->root_list))
1215		list_add_tail(&root->root_list, &root->fs_info->dead_roots);
1216	spin_unlock(&root->fs_info->trans_lock);
 
1217}
1218
1219/*
1220 * update all the cowonly tree roots on disk
1221 */
1222static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
1223				    struct btrfs_root *root)
1224{
1225	struct btrfs_root *gang[8];
1226	struct btrfs_fs_info *fs_info = root->fs_info;
1227	int i;
1228	int ret;
1229	int err = 0;
1230
1231	spin_lock(&fs_info->fs_roots_radix_lock);
1232	while (1) {
1233		ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1234						 (void **)gang, 0,
1235						 ARRAY_SIZE(gang),
1236						 BTRFS_ROOT_TRANS_TAG);
1237		if (ret == 0)
1238			break;
1239		for (i = 0; i < ret; i++) {
1240			root = gang[i];
1241			radix_tree_tag_clear(&fs_info->fs_roots_radix,
1242					(unsigned long)root->root_key.objectid,
1243					BTRFS_ROOT_TRANS_TAG);
1244			spin_unlock(&fs_info->fs_roots_radix_lock);
1245
1246			btrfs_free_log(trans, root);
1247			btrfs_update_reloc_root(trans, root);
1248			btrfs_orphan_commit_root(trans, root);
1249
1250			btrfs_save_ino_cache(root, trans);
1251
1252			/* see comments in should_cow_block() */
1253			clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1254			smp_mb__after_atomic();
1255
1256			if (root->commit_root != root->node) {
1257				list_add_tail(&root->dirty_list,
1258					&trans->transaction->switch_commits);
 
 
 
1259				btrfs_set_root_node(&root->root_item,
1260						    root->node);
1261			}
1262
1263			err = btrfs_update_root(trans, fs_info->tree_root,
1264						&root->root_key,
1265						&root->root_item);
1266			spin_lock(&fs_info->fs_roots_radix_lock);
1267			if (err)
1268				break;
1269			btrfs_qgroup_free_meta_all(root);
1270		}
1271	}
1272	spin_unlock(&fs_info->fs_roots_radix_lock);
1273	return err;
1274}
1275
1276/*
1277 * defrag a given btree.
1278 * Every leaf in the btree is read and defragged.
1279 */
1280int btrfs_defrag_root(struct btrfs_root *root)
1281{
1282	struct btrfs_fs_info *info = root->fs_info;
1283	struct btrfs_trans_handle *trans;
1284	int ret;
 
1285
1286	if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1287		return 0;
1288
1289	while (1) {
1290		trans = btrfs_start_transaction(root, 0);
1291		if (IS_ERR(trans))
1292			return PTR_ERR(trans);
1293
1294		ret = btrfs_defrag_leaves(trans, root);
1295
 
1296		btrfs_end_transaction(trans, root);
1297		btrfs_btree_balance_dirty(info->tree_root);
1298		cond_resched();
1299
1300		if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
1301			break;
1302
1303		if (btrfs_defrag_cancelled(root->fs_info)) {
1304			pr_debug("BTRFS: defrag_root cancelled\n");
1305			ret = -EAGAIN;
1306			break;
1307		}
1308	}
1309	clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1310	return ret;
1311}
1312
1313/*
1314 * new snapshots need to be created at a very specific time in the
1315 * transaction commit.  This does the actual creation.
1316 *
1317 * Note:
1318 * If the error which may affect the commitment of the current transaction
1319 * happens, we should return the error number. If the error which just affect
1320 * the creation of the pending snapshots, just return 0.
1321 */
1322static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1323				   struct btrfs_fs_info *fs_info,
1324				   struct btrfs_pending_snapshot *pending)
1325{
1326	struct btrfs_key key;
1327	struct btrfs_root_item *new_root_item;
1328	struct btrfs_root *tree_root = fs_info->tree_root;
1329	struct btrfs_root *root = pending->root;
1330	struct btrfs_root *parent_root;
1331	struct btrfs_block_rsv *rsv;
1332	struct inode *parent_inode;
1333	struct btrfs_path *path;
1334	struct btrfs_dir_item *dir_item;
1335	struct dentry *dentry;
1336	struct extent_buffer *tmp;
1337	struct extent_buffer *old;
1338	struct timespec cur_time;
1339	int ret = 0;
1340	u64 to_reserve = 0;
1341	u64 index = 0;
1342	u64 objectid;
1343	u64 root_flags;
1344	uuid_le new_uuid;
1345
1346	ASSERT(pending->path);
1347	path = pending->path;
1348
1349	ASSERT(pending->root_item);
1350	new_root_item = pending->root_item;
1351
1352	pending->error = btrfs_find_free_objectid(tree_root, &objectid);
1353	if (pending->error)
1354		goto no_free_objectid;
 
 
1355
1356	/*
1357	 * Make qgroup to skip current new snapshot's qgroupid, as it is
1358	 * accounted by later btrfs_qgroup_inherit().
1359	 */
1360	btrfs_set_skip_qgroup(trans, objectid);
1361
1362	btrfs_reloc_pre_snapshot(pending, &to_reserve);
1363
1364	if (to_reserve > 0) {
1365		pending->error = btrfs_block_rsv_add(root,
1366						     &pending->block_rsv,
1367						     to_reserve,
1368						     BTRFS_RESERVE_NO_FLUSH);
1369		if (pending->error)
1370			goto clear_skip_qgroup;
1371	}
1372
1373	key.objectid = objectid;
1374	key.offset = (u64)-1;
1375	key.type = BTRFS_ROOT_ITEM_KEY;
1376
1377	rsv = trans->block_rsv;
1378	trans->block_rsv = &pending->block_rsv;
1379	trans->bytes_reserved = trans->block_rsv->reserved;
1380	trace_btrfs_space_reservation(root->fs_info, "transaction",
1381				      trans->transid,
1382				      trans->bytes_reserved, 1);
1383	dentry = pending->dentry;
1384	parent_inode = pending->dir;
 
1385	parent_root = BTRFS_I(parent_inode)->root;
1386	record_root_in_trans(trans, parent_root);
1387
1388	cur_time = current_fs_time(parent_inode->i_sb);
1389
1390	/*
1391	 * insert the directory item
1392	 */
1393	ret = btrfs_set_inode_index(parent_inode, &index);
1394	BUG_ON(ret); /* -ENOMEM */
1395
1396	/* check if there is a file/dir which has the same name. */
1397	dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1398					 btrfs_ino(parent_inode),
1399					 dentry->d_name.name,
1400					 dentry->d_name.len, 0);
1401	if (dir_item != NULL && !IS_ERR(dir_item)) {
1402		pending->error = -EEXIST;
1403		goto dir_item_existed;
1404	} else if (IS_ERR(dir_item)) {
1405		ret = PTR_ERR(dir_item);
1406		btrfs_abort_transaction(trans, root, ret);
1407		goto fail;
 
 
1408	}
1409	btrfs_release_path(path);
 
 
 
 
 
1410
1411	/*
1412	 * pull in the delayed directory update
1413	 * and the delayed inode item
1414	 * otherwise we corrupt the FS during
1415	 * snapshot
1416	 */
1417	ret = btrfs_run_delayed_items(trans, root);
1418	if (ret) {	/* Transaction aborted */
1419		btrfs_abort_transaction(trans, root, ret);
1420		goto fail;
1421	}
1422
1423	record_root_in_trans(trans, root);
1424	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1425	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1426	btrfs_check_and_init_root_item(new_root_item);
1427
1428	root_flags = btrfs_root_flags(new_root_item);
1429	if (pending->readonly)
1430		root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1431	else
1432		root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1433	btrfs_set_root_flags(new_root_item, root_flags);
1434
1435	btrfs_set_root_generation_v2(new_root_item,
1436			trans->transid);
1437	uuid_le_gen(&new_uuid);
1438	memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
1439	memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1440			BTRFS_UUID_SIZE);
1441	if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1442		memset(new_root_item->received_uuid, 0,
1443		       sizeof(new_root_item->received_uuid));
1444		memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1445		memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1446		btrfs_set_root_stransid(new_root_item, 0);
1447		btrfs_set_root_rtransid(new_root_item, 0);
1448	}
1449	btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1450	btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1451	btrfs_set_root_otransid(new_root_item, trans->transid);
1452
1453	old = btrfs_lock_root_node(root);
1454	ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1455	if (ret) {
1456		btrfs_tree_unlock(old);
1457		free_extent_buffer(old);
1458		btrfs_abort_transaction(trans, root, ret);
1459		goto fail;
1460	}
1461
1462	btrfs_set_lock_blocking(old);
1463
1464	ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1465	/* clean up in any case */
1466	btrfs_tree_unlock(old);
1467	free_extent_buffer(old);
1468	if (ret) {
1469		btrfs_abort_transaction(trans, root, ret);
1470		goto fail;
1471	}
1472	/* see comments in should_cow_block() */
1473	set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1474	smp_wmb();
1475
1476	btrfs_set_root_node(new_root_item, tmp);
1477	/* record when the snapshot was created in key.offset */
1478	key.offset = trans->transid;
1479	ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1480	btrfs_tree_unlock(tmp);
1481	free_extent_buffer(tmp);
1482	if (ret) {
1483		btrfs_abort_transaction(trans, root, ret);
1484		goto fail;
1485	}
1486
1487	/*
1488	 * insert root back/forward references
1489	 */
1490	ret = btrfs_add_root_ref(trans, tree_root, objectid,
1491				 parent_root->root_key.objectid,
1492				 btrfs_ino(parent_inode), index,
1493				 dentry->d_name.name, dentry->d_name.len);
1494	if (ret) {
1495		btrfs_abort_transaction(trans, root, ret);
1496		goto fail;
1497	}
1498
1499	key.offset = (u64)-1;
1500	pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1501	if (IS_ERR(pending->snap)) {
1502		ret = PTR_ERR(pending->snap);
1503		btrfs_abort_transaction(trans, root, ret);
1504		goto fail;
1505	}
1506
1507	ret = btrfs_reloc_post_snapshot(trans, pending);
1508	if (ret) {
1509		btrfs_abort_transaction(trans, root, ret);
1510		goto fail;
1511	}
1512
1513	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1514	if (ret) {
1515		btrfs_abort_transaction(trans, root, ret);
1516		goto fail;
1517	}
1518
1519	ret = btrfs_insert_dir_item(trans, parent_root,
1520				    dentry->d_name.name, dentry->d_name.len,
1521				    parent_inode, &key,
1522				    BTRFS_FT_DIR, index);
1523	/* We have check then name at the beginning, so it is impossible. */
1524	BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1525	if (ret) {
1526		btrfs_abort_transaction(trans, root, ret);
1527		goto fail;
1528	}
1529
1530	btrfs_i_size_write(parent_inode, parent_inode->i_size +
1531					 dentry->d_name.len * 2);
1532	parent_inode->i_mtime = parent_inode->i_ctime =
1533		current_fs_time(parent_inode->i_sb);
1534	ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
1535	if (ret) {
1536		btrfs_abort_transaction(trans, root, ret);
1537		goto fail;
1538	}
1539	ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_uuid.b,
1540				  BTRFS_UUID_KEY_SUBVOL, objectid);
1541	if (ret) {
1542		btrfs_abort_transaction(trans, root, ret);
1543		goto fail;
1544	}
1545	if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1546		ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
1547					  new_root_item->received_uuid,
1548					  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1549					  objectid);
1550		if (ret && ret != -EEXIST) {
1551			btrfs_abort_transaction(trans, root, ret);
1552			goto fail;
1553		}
1554	}
1555
1556	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1557	if (ret) {
1558		btrfs_abort_transaction(trans, root, ret);
1559		goto fail;
1560	}
1561
1562	/*
1563	 * account qgroup counters before qgroup_inherit()
1564	 */
1565	ret = btrfs_qgroup_prepare_account_extents(trans, fs_info);
1566	if (ret)
1567		goto fail;
1568	ret = btrfs_qgroup_account_extents(trans, fs_info);
1569	if (ret)
1570		goto fail;
1571	ret = btrfs_qgroup_inherit(trans, fs_info,
1572				   root->root_key.objectid,
1573				   objectid, pending->inherit);
1574	if (ret) {
1575		btrfs_abort_transaction(trans, root, ret);
1576		goto fail;
1577	}
1578
1579fail:
1580	pending->error = ret;
1581dir_item_existed:
1582	trans->block_rsv = rsv;
1583	trans->bytes_reserved = 0;
1584clear_skip_qgroup:
1585	btrfs_clear_skip_qgroup(trans);
1586no_free_objectid:
1587	kfree(new_root_item);
1588	pending->root_item = NULL;
1589	btrfs_free_path(path);
1590	pending->path = NULL;
1591
1592	return ret;
 
 
 
 
 
 
1593}
1594
1595/*
1596 * create all the snapshots we've scheduled for creation
1597 */
1598static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1599					     struct btrfs_fs_info *fs_info)
1600{
1601	struct btrfs_pending_snapshot *pending, *next;
1602	struct list_head *head = &trans->transaction->pending_snapshots;
1603	int ret = 0;
1604
1605	list_for_each_entry_safe(pending, next, head, list) {
1606		list_del(&pending->list);
1607		ret = create_pending_snapshot(trans, fs_info, pending);
1608		if (ret)
1609			break;
1610	}
1611	return ret;
1612}
1613
1614static void update_super_roots(struct btrfs_root *root)
1615{
1616	struct btrfs_root_item *root_item;
1617	struct btrfs_super_block *super;
1618
1619	super = root->fs_info->super_copy;
1620
1621	root_item = &root->fs_info->chunk_root->root_item;
1622	super->chunk_root = root_item->bytenr;
1623	super->chunk_root_generation = root_item->generation;
1624	super->chunk_root_level = root_item->level;
1625
1626	root_item = &root->fs_info->tree_root->root_item;
1627	super->root = root_item->bytenr;
1628	super->generation = root_item->generation;
1629	super->root_level = root_item->level;
1630	if (btrfs_test_opt(root, SPACE_CACHE))
1631		super->cache_generation = root_item->generation;
1632	if (root->fs_info->update_uuid_tree_gen)
1633		super->uuid_tree_generation = root_item->generation;
1634}
1635
1636int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1637{
1638	struct btrfs_transaction *trans;
1639	int ret = 0;
1640
1641	spin_lock(&info->trans_lock);
1642	trans = info->running_transaction;
1643	if (trans)
1644		ret = (trans->state >= TRANS_STATE_COMMIT_START);
1645	spin_unlock(&info->trans_lock);
1646	return ret;
1647}
1648
1649int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1650{
1651	struct btrfs_transaction *trans;
1652	int ret = 0;
1653
1654	spin_lock(&info->trans_lock);
1655	trans = info->running_transaction;
1656	if (trans)
1657		ret = is_transaction_blocked(trans);
1658	spin_unlock(&info->trans_lock);
1659	return ret;
1660}
1661
1662/*
1663 * wait for the current transaction commit to start and block subsequent
1664 * transaction joins
1665 */
1666static void wait_current_trans_commit_start(struct btrfs_root *root,
1667					    struct btrfs_transaction *trans)
1668{
1669	wait_event(root->fs_info->transaction_blocked_wait,
1670		   trans->state >= TRANS_STATE_COMMIT_START ||
1671		   trans->aborted);
1672}
1673
1674/*
1675 * wait for the current transaction to start and then become unblocked.
1676 * caller holds ref.
1677 */
1678static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1679					 struct btrfs_transaction *trans)
1680{
1681	wait_event(root->fs_info->transaction_wait,
1682		   trans->state >= TRANS_STATE_UNBLOCKED ||
1683		   trans->aborted);
1684}
1685
1686/*
1687 * commit transactions asynchronously. once btrfs_commit_transaction_async
1688 * returns, any subsequent transaction will not be allowed to join.
1689 */
1690struct btrfs_async_commit {
1691	struct btrfs_trans_handle *newtrans;
1692	struct btrfs_root *root;
1693	struct work_struct work;
1694};
1695
1696static void do_async_commit(struct work_struct *work)
1697{
1698	struct btrfs_async_commit *ac =
1699		container_of(work, struct btrfs_async_commit, work);
1700
1701	/*
1702	 * We've got freeze protection passed with the transaction.
1703	 * Tell lockdep about it.
1704	 */
1705	if (ac->newtrans->type & __TRANS_FREEZABLE)
1706		__sb_writers_acquired(ac->root->fs_info->sb, SB_FREEZE_FS);
1707
1708	current->journal_info = ac->newtrans;
1709
1710	btrfs_commit_transaction(ac->newtrans, ac->root);
1711	kfree(ac);
1712}
1713
1714int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1715				   struct btrfs_root *root,
1716				   int wait_for_unblock)
1717{
1718	struct btrfs_async_commit *ac;
1719	struct btrfs_transaction *cur_trans;
1720
1721	ac = kmalloc(sizeof(*ac), GFP_NOFS);
1722	if (!ac)
1723		return -ENOMEM;
1724
1725	INIT_WORK(&ac->work, do_async_commit);
1726	ac->root = root;
1727	ac->newtrans = btrfs_join_transaction(root);
1728	if (IS_ERR(ac->newtrans)) {
1729		int err = PTR_ERR(ac->newtrans);
1730		kfree(ac);
1731		return err;
1732	}
1733
1734	/* take transaction reference */
1735	cur_trans = trans->transaction;
1736	atomic_inc(&cur_trans->use_count);
1737
1738	btrfs_end_transaction(trans, root);
1739
1740	/*
1741	 * Tell lockdep we've released the freeze rwsem, since the
1742	 * async commit thread will be the one to unlock it.
1743	 */
1744	if (ac->newtrans->type & __TRANS_FREEZABLE)
1745		__sb_writers_release(root->fs_info->sb, SB_FREEZE_FS);
1746
1747	schedule_work(&ac->work);
1748
1749	/* wait for transaction to start and unblock */
1750	if (wait_for_unblock)
1751		wait_current_trans_commit_start_and_unblock(root, cur_trans);
1752	else
1753		wait_current_trans_commit_start(root, cur_trans);
1754
1755	if (current->journal_info == trans)
1756		current->journal_info = NULL;
1757
1758	btrfs_put_transaction(cur_trans);
1759	return 0;
1760}
1761
1762
1763static void cleanup_transaction(struct btrfs_trans_handle *trans,
1764				struct btrfs_root *root, int err)
1765{
1766	struct btrfs_transaction *cur_trans = trans->transaction;
1767	DEFINE_WAIT(wait);
1768
1769	WARN_ON(trans->use_count > 1);
1770
1771	btrfs_abort_transaction(trans, root, err);
1772
1773	spin_lock(&root->fs_info->trans_lock);
1774
1775	/*
1776	 * If the transaction is removed from the list, it means this
1777	 * transaction has been committed successfully, so it is impossible
1778	 * to call the cleanup function.
1779	 */
1780	BUG_ON(list_empty(&cur_trans->list));
1781
1782	list_del_init(&cur_trans->list);
1783	if (cur_trans == root->fs_info->running_transaction) {
1784		cur_trans->state = TRANS_STATE_COMMIT_DOING;
1785		spin_unlock(&root->fs_info->trans_lock);
1786		wait_event(cur_trans->writer_wait,
1787			   atomic_read(&cur_trans->num_writers) == 1);
1788
1789		spin_lock(&root->fs_info->trans_lock);
1790	}
1791	spin_unlock(&root->fs_info->trans_lock);
1792
1793	btrfs_cleanup_one_transaction(trans->transaction, root);
1794
1795	spin_lock(&root->fs_info->trans_lock);
1796	if (cur_trans == root->fs_info->running_transaction)
1797		root->fs_info->running_transaction = NULL;
1798	spin_unlock(&root->fs_info->trans_lock);
1799
1800	if (trans->type & __TRANS_FREEZABLE)
1801		sb_end_intwrite(root->fs_info->sb);
1802	btrfs_put_transaction(cur_trans);
1803	btrfs_put_transaction(cur_trans);
1804
1805	trace_btrfs_transaction_commit(root);
1806
 
 
1807	if (current->journal_info == trans)
1808		current->journal_info = NULL;
1809	btrfs_scrub_cancel(root->fs_info);
1810
1811	kmem_cache_free(btrfs_trans_handle_cachep, trans);
1812}
1813
1814static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
1815{
1816	if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT))
1817		return btrfs_start_delalloc_roots(fs_info, 1, -1);
1818	return 0;
1819}
1820
1821static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
1822{
1823	if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT))
1824		btrfs_wait_ordered_roots(fs_info, -1);
1825}
1826
1827static inline void
1828btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans)
1829{
1830	wait_event(cur_trans->pending_wait,
1831		   atomic_read(&cur_trans->pending_ordered) == 0);
1832}
1833
1834int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1835			     struct btrfs_root *root)
1836{
 
1837	struct btrfs_transaction *cur_trans = trans->transaction;
1838	struct btrfs_transaction *prev_trans = NULL;
1839	struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode);
1840	int ret;
 
 
 
1841
1842	/* Stop the commit early if ->aborted is set */
1843	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1844		ret = cur_trans->aborted;
1845		btrfs_end_transaction(trans, root);
1846		return ret;
1847	}
 
1848
1849	/* make a pass through all the delayed refs we have so far
1850	 * any runnings procs may add more while we are here
1851	 */
1852	ret = btrfs_run_delayed_refs(trans, root, 0);
1853	if (ret) {
1854		btrfs_end_transaction(trans, root);
1855		return ret;
1856	}
1857
1858	btrfs_trans_release_metadata(trans, root);
1859	trans->block_rsv = NULL;
1860
1861	cur_trans = trans->transaction;
1862
1863	/*
1864	 * set the flushing flag so procs in this transaction have to
1865	 * start sending their work down.
1866	 */
1867	cur_trans->delayed_refs.flushing = 1;
1868	smp_wmb();
1869
1870	if (!list_empty(&trans->new_bgs))
1871		btrfs_create_pending_block_groups(trans, root);
1872
1873	ret = btrfs_run_delayed_refs(trans, root, 0);
1874	if (ret) {
1875		btrfs_end_transaction(trans, root);
1876		return ret;
1877	}
1878
1879	if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
1880		int run_it = 0;
1881
1882		/* this mutex is also taken before trying to set
1883		 * block groups readonly.  We need to make sure
1884		 * that nobody has set a block group readonly
1885		 * after a extents from that block group have been
1886		 * allocated for cache files.  btrfs_set_block_group_ro
1887		 * will wait for the transaction to commit if it
1888		 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
1889		 *
1890		 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
1891		 * only one process starts all the block group IO.  It wouldn't
1892		 * hurt to have more than one go through, but there's no
1893		 * real advantage to it either.
1894		 */
1895		mutex_lock(&root->fs_info->ro_block_group_mutex);
1896		if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
1897				      &cur_trans->flags))
1898			run_it = 1;
1899		mutex_unlock(&root->fs_info->ro_block_group_mutex);
1900
1901		if (run_it)
1902			ret = btrfs_start_dirty_block_groups(trans, root);
1903	}
1904	if (ret) {
1905		btrfs_end_transaction(trans, root);
1906		return ret;
1907	}
1908
1909	spin_lock(&root->fs_info->trans_lock);
1910	if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
1911		spin_unlock(&root->fs_info->trans_lock);
1912		atomic_inc(&cur_trans->use_count);
1913		ret = btrfs_end_transaction(trans, root);
1914
1915		wait_for_commit(root, cur_trans);
1916
1917		if (unlikely(cur_trans->aborted))
1918			ret = cur_trans->aborted;
1919
1920		btrfs_put_transaction(cur_trans);
1921
1922		return ret;
1923	}
1924
1925	cur_trans->state = TRANS_STATE_COMMIT_START;
 
 
1926	wake_up(&root->fs_info->transaction_blocked_wait);
1927
 
1928	if (cur_trans->list.prev != &root->fs_info->trans_list) {
1929		prev_trans = list_entry(cur_trans->list.prev,
1930					struct btrfs_transaction, list);
1931		if (prev_trans->state != TRANS_STATE_COMPLETED) {
1932			atomic_inc(&prev_trans->use_count);
1933			spin_unlock(&root->fs_info->trans_lock);
1934
1935			wait_for_commit(root, prev_trans);
1936			ret = prev_trans->aborted;
1937
1938			btrfs_put_transaction(prev_trans);
1939			if (ret)
1940				goto cleanup_transaction;
1941		} else {
1942			spin_unlock(&root->fs_info->trans_lock);
1943		}
1944	} else {
1945		spin_unlock(&root->fs_info->trans_lock);
1946	}
1947
1948	extwriter_counter_dec(cur_trans, trans->type);
 
1949
1950	ret = btrfs_start_delalloc_flush(root->fs_info);
1951	if (ret)
1952		goto cleanup_transaction;
1953
1954	ret = btrfs_run_delayed_items(trans, root);
1955	if (ret)
1956		goto cleanup_transaction;
1957
1958	wait_event(cur_trans->writer_wait,
1959		   extwriter_counter_read(cur_trans) == 0);
1960
1961	/* some pending stuffs might be added after the previous flush. */
1962	ret = btrfs_run_delayed_items(trans, root);
1963	if (ret)
1964		goto cleanup_transaction;
 
 
 
 
 
 
 
 
 
 
 
 
 
1965
1966	btrfs_wait_delalloc_flush(root->fs_info);
 
1967
1968	btrfs_wait_pending_ordered(cur_trans);
 
 
 
 
 
 
 
1969
1970	btrfs_scrub_pause(root);
1971	/*
1972	 * Ok now we need to make sure to block out any other joins while we
1973	 * commit the transaction.  We could have started a join before setting
1974	 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
1975	 */
1976	spin_lock(&root->fs_info->trans_lock);
1977	cur_trans->state = TRANS_STATE_COMMIT_DOING;
1978	spin_unlock(&root->fs_info->trans_lock);
1979	wait_event(cur_trans->writer_wait,
1980		   atomic_read(&cur_trans->num_writers) == 1);
1981
1982	/* ->aborted might be set after the previous check, so check it */
1983	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1984		ret = cur_trans->aborted;
1985		goto scrub_continue;
1986	}
1987	/*
1988	 * the reloc mutex makes sure that we stop
1989	 * the balancing code from coming in and moving
1990	 * extents around in the middle of the commit
1991	 */
1992	mutex_lock(&root->fs_info->reloc_mutex);
1993
1994	/*
1995	 * We needn't worry about the delayed items because we will
1996	 * deal with them in create_pending_snapshot(), which is the
1997	 * core function of the snapshot creation.
1998	 */
1999	ret = create_pending_snapshots(trans, root->fs_info);
2000	if (ret) {
2001		mutex_unlock(&root->fs_info->reloc_mutex);
2002		goto scrub_continue;
2003	}
2004
2005	/*
2006	 * We insert the dir indexes of the snapshots and update the inode
2007	 * of the snapshots' parents after the snapshot creation, so there
2008	 * are some delayed items which are not dealt with. Now deal with
2009	 * them.
2010	 *
2011	 * We needn't worry that this operation will corrupt the snapshots,
2012	 * because all the tree which are snapshoted will be forced to COW
2013	 * the nodes and leaves.
2014	 */
2015	ret = btrfs_run_delayed_items(trans, root);
2016	if (ret) {
2017		mutex_unlock(&root->fs_info->reloc_mutex);
2018		goto scrub_continue;
2019	}
2020
2021	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
2022	if (ret) {
2023		mutex_unlock(&root->fs_info->reloc_mutex);
2024		goto scrub_continue;
2025	}
2026
2027	/* Reocrd old roots for later qgroup accounting */
2028	ret = btrfs_qgroup_prepare_account_extents(trans, root->fs_info);
2029	if (ret) {
2030		mutex_unlock(&root->fs_info->reloc_mutex);
2031		goto scrub_continue;
2032	}
2033
2034	/*
2035	 * make sure none of the code above managed to slip in a
2036	 * delayed item
2037	 */
2038	btrfs_assert_delayed_root_empty(root);
2039
2040	WARN_ON(cur_trans != trans->transaction);
2041
 
2042	/* btrfs_commit_tree_roots is responsible for getting the
2043	 * various roots consistent with each other.  Every pointer
2044	 * in the tree of tree roots has to point to the most up to date
2045	 * root for every subvolume and other tree.  So, we have to keep
2046	 * the tree logging code from jumping in and changing any
2047	 * of the trees.
2048	 *
2049	 * At this point in the commit, there can't be any tree-log
2050	 * writers, but a little lower down we drop the trans mutex
2051	 * and let new people in.  By holding the tree_log_mutex
2052	 * from now until after the super is written, we avoid races
2053	 * with the tree-log code.
2054	 */
2055	mutex_lock(&root->fs_info->tree_log_mutex);
2056
2057	ret = commit_fs_roots(trans, root);
2058	if (ret) {
2059		mutex_unlock(&root->fs_info->tree_log_mutex);
2060		mutex_unlock(&root->fs_info->reloc_mutex);
2061		goto scrub_continue;
2062	}
2063
2064	/*
2065	 * Since the transaction is done, we can apply the pending changes
2066	 * before the next transaction.
2067	 */
2068	btrfs_apply_pending_changes(root->fs_info);
2069
2070	/* commit_fs_roots gets rid of all the tree log roots, it is now
2071	 * safe to free the root of tree log roots
2072	 */
2073	btrfs_free_log_root_tree(trans, root->fs_info);
2074
2075	/*
2076	 * Since fs roots are all committed, we can get a quite accurate
2077	 * new_roots. So let's do quota accounting.
2078	 */
2079	ret = btrfs_qgroup_account_extents(trans, root->fs_info);
2080	if (ret < 0) {
2081		mutex_unlock(&root->fs_info->tree_log_mutex);
2082		mutex_unlock(&root->fs_info->reloc_mutex);
2083		goto scrub_continue;
2084	}
2085
2086	ret = commit_cowonly_roots(trans, root);
2087	if (ret) {
2088		mutex_unlock(&root->fs_info->tree_log_mutex);
2089		mutex_unlock(&root->fs_info->reloc_mutex);
2090		goto scrub_continue;
2091	}
2092
2093	/*
2094	 * The tasks which save the space cache and inode cache may also
2095	 * update ->aborted, check it.
2096	 */
2097	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
2098		ret = cur_trans->aborted;
2099		mutex_unlock(&root->fs_info->tree_log_mutex);
2100		mutex_unlock(&root->fs_info->reloc_mutex);
2101		goto scrub_continue;
2102	}
2103
2104	btrfs_prepare_extent_commit(trans, root);
2105
2106	cur_trans = root->fs_info->running_transaction;
2107
2108	btrfs_set_root_node(&root->fs_info->tree_root->root_item,
2109			    root->fs_info->tree_root->node);
2110	list_add_tail(&root->fs_info->tree_root->dirty_list,
2111		      &cur_trans->switch_commits);
2112
2113	btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
2114			    root->fs_info->chunk_root->node);
2115	list_add_tail(&root->fs_info->chunk_root->dirty_list,
2116		      &cur_trans->switch_commits);
2117
2118	switch_commit_roots(cur_trans, root->fs_info);
2119
2120	assert_qgroups_uptodate(trans);
2121	ASSERT(list_empty(&cur_trans->dirty_bgs));
2122	ASSERT(list_empty(&cur_trans->io_bgs));
2123	update_super_roots(root);
2124
2125	btrfs_set_super_log_root(root->fs_info->super_copy, 0);
2126	btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
 
 
 
2127	memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
2128	       sizeof(*root->fs_info->super_copy));
2129
2130	btrfs_update_commit_device_size(root->fs_info);
2131	btrfs_update_commit_device_bytes_used(root, cur_trans);
2132
2133	clear_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags);
2134	clear_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags);
2135
2136	btrfs_trans_release_chunk_metadata(trans);
2137
2138	spin_lock(&root->fs_info->trans_lock);
2139	cur_trans->state = TRANS_STATE_UNBLOCKED;
2140	root->fs_info->running_transaction = NULL;
 
2141	spin_unlock(&root->fs_info->trans_lock);
2142	mutex_unlock(&root->fs_info->reloc_mutex);
2143
2144	wake_up(&root->fs_info->transaction_wait);
2145
2146	ret = btrfs_write_and_wait_transaction(trans, root);
2147	if (ret) {
2148		btrfs_std_error(root->fs_info, ret,
2149			    "Error while writing out transaction");
2150		mutex_unlock(&root->fs_info->tree_log_mutex);
2151		goto scrub_continue;
2152	}
2153
2154	ret = write_ctree_super(trans, root, 0);
2155	if (ret) {
2156		mutex_unlock(&root->fs_info->tree_log_mutex);
2157		goto scrub_continue;
2158	}
2159
2160	/*
2161	 * the super is written, we can safely allow the tree-loggers
2162	 * to go about their business
2163	 */
2164	mutex_unlock(&root->fs_info->tree_log_mutex);
2165
2166	btrfs_finish_extent_commit(trans, root);
2167
2168	if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2169		btrfs_clear_space_info_full(root->fs_info);
2170
2171	root->fs_info->last_trans_committed = cur_trans->transid;
2172	/*
2173	 * We needn't acquire the lock here because there is no other task
2174	 * which can change it.
2175	 */
2176	cur_trans->state = TRANS_STATE_COMPLETED;
2177	wake_up(&cur_trans->commit_wait);
2178
2179	spin_lock(&root->fs_info->trans_lock);
2180	list_del_init(&cur_trans->list);
2181	spin_unlock(&root->fs_info->trans_lock);
2182
2183	btrfs_put_transaction(cur_trans);
2184	btrfs_put_transaction(cur_trans);
2185
2186	if (trans->type & __TRANS_FREEZABLE)
2187		sb_end_intwrite(root->fs_info->sb);
2188
2189	trace_btrfs_transaction_commit(root);
2190
2191	btrfs_scrub_continue(root);
2192
2193	if (current->journal_info == trans)
2194		current->journal_info = NULL;
2195
2196	kmem_cache_free(btrfs_trans_handle_cachep, trans);
2197
2198	if (current != root->fs_info->transaction_kthread &&
2199	    current != root->fs_info->cleaner_kthread)
2200		btrfs_run_delayed_iputs(root);
2201
2202	return ret;
2203
2204scrub_continue:
2205	btrfs_scrub_continue(root);
2206cleanup_transaction:
2207	btrfs_trans_release_metadata(trans, root);
2208	btrfs_trans_release_chunk_metadata(trans);
2209	trans->block_rsv = NULL;
2210	btrfs_warn(root->fs_info, "Skipping commit of aborted transaction.");
2211	if (current->journal_info == trans)
2212		current->journal_info = NULL;
2213	cleanup_transaction(trans, root, ret);
2214
2215	return ret;
2216}
2217
2218/*
2219 * return < 0 if error
2220 * 0 if there are no more dead_roots at the time of call
2221 * 1 there are more to be processed, call me again
2222 *
2223 * The return value indicates there are certainly more snapshots to delete, but
2224 * if there comes a new one during processing, it may return 0. We don't mind,
2225 * because btrfs_commit_super will poke cleaner thread and it will process it a
2226 * few seconds later.
2227 */
2228int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
2229{
2230	int ret;
2231	struct btrfs_fs_info *fs_info = root->fs_info;
2232
2233	spin_lock(&fs_info->trans_lock);
2234	if (list_empty(&fs_info->dead_roots)) {
2235		spin_unlock(&fs_info->trans_lock);
2236		return 0;
2237	}
2238	root = list_first_entry(&fs_info->dead_roots,
2239			struct btrfs_root, root_list);
2240	list_del_init(&root->root_list);
2241	spin_unlock(&fs_info->trans_lock);
2242
2243	pr_debug("BTRFS: cleaner removing %llu\n", root->objectid);
2244
2245	btrfs_kill_all_delayed_nodes(root);
2246
2247	if (btrfs_header_backref_rev(root->node) <
2248			BTRFS_MIXED_BACKREF_REV)
2249		ret = btrfs_drop_snapshot(root, NULL, 0, 0);
2250	else
2251		ret = btrfs_drop_snapshot(root, NULL, 1, 0);
2252
2253	return (ret < 0) ? 0 : 1;
2254}
2255
2256void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2257{
2258	unsigned long prev;
2259	unsigned long bit;
2260
2261	prev = xchg(&fs_info->pending_changes, 0);
2262	if (!prev)
2263		return;
2264
2265	bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
2266	if (prev & bit)
2267		btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2268	prev &= ~bit;
2269
2270	bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
2271	if (prev & bit)
2272		btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2273	prev &= ~bit;
2274
2275	bit = 1 << BTRFS_PENDING_COMMIT;
2276	if (prev & bit)
2277		btrfs_debug(fs_info, "pending commit done");
2278	prev &= ~bit;
2279
2280	if (prev)
2281		btrfs_warn(fs_info,
2282			"unknown pending changes left 0x%lx, ignoring", prev);
2283}