16 #include "transaction.h"
29  * Transaction states and transitions
31  * No running transaction (fs tree blocks are not modified)
36  * Transaction N [[TRANS_STATE_RUNNING]]
38  * | New trans handles can be attached to transaction N by calling all
43  * |  transaction N
45  * Transaction N [[TRANS_STATE_COMMIT_START]]
47  * | Will wait for previous running transaction to completely finish if there
53  * | - Wait for current transaction to be committed by others.
57  * | to this running transaction.
59  * | transaction N+1.
62  * |  Caller is chosen to commit transaction N, and all other trans handle
65  * Transaction N [[TRANS_STATE_COMMIT_DOING]]
67  * | The heavy lifting transaction work is started.
74  * | transaction to finish and attach to transaction N+1.
79  * Transaction N [[TRANS_STATE_UNBLOCKED]]
80  * |						    Transaction N+1
85  * | At this stage, new transaction is allowed to   |
94  * Transaction N [[TRANS_STATE_COMPLETED]]	    V
95  *   All tree blocks and super blocks are written.  Transaction N+1
96  *   This transaction is finished and all its	    [[TRANS_STATE_COMMIT_START]]
123 void btrfs_put_transaction(struct btrfs_transaction *transaction)  in btrfs_put_transaction()  argument
125 	WARN_ON(refcount_read(&transaction->use_count) == 0);  in btrfs_put_transaction()
126 	if (refcount_dec_and_test(&transaction->use_count)) {  in btrfs_put_transaction()
127 		BUG_ON(!list_empty(&transaction->list));  in btrfs_put_transaction()
129 				&transaction->delayed_refs.href_root.rb_root));  in btrfs_put_transaction()
131 				&transaction->delayed_refs.dirty_extent_root));  in btrfs_put_transaction()
132 		if (transaction->delayed_refs.pending_csums)  in btrfs_put_transaction()
133 			btrfs_err(transaction->fs_info,  in btrfs_put_transaction()
135 				  transaction->delayed_refs.pending_csums);  in btrfs_put_transaction()
138 		 * because the transaction was aborted and a commit did not  in btrfs_put_transaction()
143 		while (!list_empty(&transaction->deleted_bgs)) {  in btrfs_put_transaction()
146 			cache = list_first_entry(&transaction->deleted_bgs,  in btrfs_put_transaction()
153 		WARN_ON(!list_empty(&transaction->dev_update_list));  in btrfs_put_transaction()
154 		kfree(transaction);  in btrfs_put_transaction()
160 	struct btrfs_transaction *cur_trans = trans->transaction;  in switch_commit_roots()
276  * either allocate a new transaction or hop into the existing one
310 	 * If we are ATTACH, we just want to catch the current transaction,  in join_transaction()
311 	 * and commit it. If there is no transaction, just return ENOENT.  in join_transaction()
317 	 * JOIN_NOLOCK only happens during the transaction commit, so  in join_transaction()
329 		 * someone started a transaction after we unlocked.  Make sure  in join_transaction()
350 	 * commit the transaction.  in join_transaction()
363 	 * although the tree mod log is per file system and not per transaction,  in join_transaction()
364 	 * the log must never go across transaction boundaries.  in join_transaction()
368 		WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");  in join_transaction()
370 		WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");  in join_transaction()
403  * is properly recorded in a given transaction.  This is required to make sure
404  * the old root from before we joined the transaction is deleted when the
405  * transaction commits.
445 		 * this transaction.  in record_root_in_trans()
473 	struct btrfs_transaction *cur_trans = trans->transaction;  in btrfs_add_dropped_root()
475 	/* Add ourselves to the transaction dropped list */  in btrfs_add_dropped_root()
520 /* wait for commit against the current transaction to become unblocked
521  * when this is done, it is safe to start a new transaction, but the current
522  * transaction might not be fully on disk.
596 	 * Do the reservation before we join the transaction so we can do all  in start_transaction()
611 		 * we only do 1 enospc flushing cycle per transaction start.  We  in start_transaction()
663 	 * If we are JOIN_NOLOCK we're already committing a transaction and  in start_transaction()
670 	 * transaction and commit it, so we needn't do sb_start_intwrite().   in start_transaction()
694 	h->transaction = cur_trans;  in start_transaction()
711 		trace_btrfs_space_reservation(fs_info, "transaction",  in start_transaction()
738 	 * transaction.  in start_transaction()
746 		 * The transaction handle is fully initialized and linked with  in start_transaction()
797  * Similar to regular join but it never starts a transaction when none is
807  * btrfs_attach_transaction() - catch the running transaction
809  * It is used when we want to commit the current the transaction, but
813  * running transaction. But it is possible that the inactive transaction
815  * inactive transaction in the fs when -ENOENT is returned, you should
826  * btrfs_attach_transaction_barrier() - catch the running transaction
845 /* Wait for a transaction commit to reach at least the given state. */
861 		/* find specified transaction */  in btrfs_wait_for_commit()
878 		 * The specified transaction doesn't exist, or we  in btrfs_wait_for_commit()
887 		/* find newest transaction that is committing | committed */  in btrfs_wait_for_commit()
927 	struct btrfs_transaction *cur_trans = trans->transaction;  in btrfs_should_end_transaction()
950 	trace_btrfs_space_reservation(fs_info, "transaction",  in btrfs_trans_release_metadata()
961 	struct btrfs_transaction *cur_trans = trans->transaction;  in __btrfs_end_transaction()
1051 		 * the transaction (through extent_io_tree_release()).  in btrfs_write_marked_extents()
1075  * those extents are on disk for transaction or log commit.  We wait
1092 		 * When committing the transaction, we'll remove any entries  in __btrfs_wait_marked_extents()
1095 		 * concurrently - we do it only at transaction commit time when  in __btrfs_wait_marked_extents()
1156  * This function ensures such extents are persisted on disk for transaction or
1159  * @trans: transaction whose dirty pages we'd like to write
1165 	struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;  in btrfs_write_and_wait_transaction()
1174 	extent_io_tree_release(&trans->transaction->dirty_pages);  in btrfs_write_and_wait_transaction()
1234 	struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;  in commit_cowonly_roots()
1235 	struct list_head *io_bgs = &trans->transaction->io_bgs;  in commit_cowonly_roots()
1273 				      &trans->transaction->switch_commits);  in commit_cowonly_roots()
1304 		      &trans->transaction->switch_commits);  in commit_cowonly_roots()
1368 					&trans->transaction->switch_commits);  in commit_fs_roots()
1429  * roots inside one transaction and write all btree into disk, to make
1477 	 * We are going to commit transaction, see btrfs_commit_transaction()  in qgroup_account_snapshot()
1496 	 * Now we do a simplified commit transaction, which will:  in qgroup_account_snapshot()
1514 			"Error while writing out transaction for qgroup");  in qgroup_account_snapshot()
1532  * transaction commit.  This does the actual creation.
1535  * If the error which may affect the commitment of the current transaction
1597 	trace_btrfs_space_reservation(fs_info, "transaction",  in create_pending_snapshot()
1636 	if (ret) {	/* Transaction aborted */  in create_pending_snapshot()
1803 	struct list_head *head = &trans->transaction->pending_snapshots;  in create_pending_snapshots()
1867  * returns, any subsequent transaction will not be allowed to join.
1880 	 * We've got freeze protection passed with the transaction.  in do_async_commit()
1910 	/* take transaction reference */  in btrfs_commit_transaction_async()
1911 	cur_trans = trans->transaction;  in btrfs_commit_transaction_async()
1925 	 * Wait for the current transaction commit to start and block  in btrfs_commit_transaction_async()
1926 	 * subsequent transaction joins  in btrfs_commit_transaction_async()
1942 	struct btrfs_transaction *cur_trans = trans->transaction;  in cleanup_transaction()
1951 	 * If the transaction is removed from the list, it means this  in cleanup_transaction()
1952 	 * transaction has been committed successfully, so it is impossible  in cleanup_transaction()
1967 	 * Now that we know no one else is still using the transaction we can  in cleanup_transaction()
1968 	 * remove the transaction from the list of transactions. This avoids  in cleanup_transaction()
1969 	 * the transaction kthread from cleaning up the transaction while some  in cleanup_transaction()
1971 	 * on things like log trees, as it forces the transaction kthread to  in cleanup_transaction()
1972 	 * wait for this transaction to be cleaned up by us.  in cleanup_transaction()
1978 	btrfs_cleanup_one_transaction(trans->transaction, fs_info);  in cleanup_transaction()
2001  * transaction and remove them from the list
2022 	 * from already being in a transaction and our join_transaction doesn't  in btrfs_start_delalloc_flush()
2039 	struct btrfs_transaction *cur_trans = trans->transaction;  in btrfs_commit_transaction()
2056 	 * We only want one transaction commit doing the flushing so we do not  in btrfs_commit_transaction()
2082 		 * will wait for the transaction to commit if it  in btrfs_commit_transaction()
2153 		 * The previous transaction was aborted and was already removed  in btrfs_commit_transaction()
2186 	 * transaction. Otherwise if this transaction commits before the ordered  in btrfs_commit_transaction()
2195 	 * commit the transaction.  We could have started a join before setting  in btrfs_commit_transaction()
2248 	WARN_ON(cur_trans != trans->transaction);  in btrfs_commit_transaction()
2270 	 * Since the transaction is done, we can apply the pending changes  in btrfs_commit_transaction()
2271 	 * before the next transaction.  in btrfs_commit_transaction()
2342 				      "Error while writing out transaction");  in btrfs_commit_transaction()
2353 	 * in this transaction. So it's now safe to free the redirtyied extent  in btrfs_commit_transaction()
2419 	btrfs_warn(fs_info, "Skipping commit of aborted transaction.");  in btrfs_commit_transaction()