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Commit b50fff81 authored by David Sterba's avatar David Sterba
Browse files

btrfs: switch to refcount_t type for btrfs_trans_handle::use_count 



The use_count is a reference counter, we can use the refcount_t type,
though we don't use the atomicity. This is not a performance critical
code and we could catch the underflows. The type is changed from long,
but the number of references will fit an int.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 2dbda74e

fs/btrfs/transaction.c

+6 −6
Original line number Diff line number Diff line
@@ -495,8 +495,8 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, 
	if (current->journal_info) {

		WARN_ON(type & TRANS_EXTWRITERS);

		h = current->journal_info;

		h->use_count++;

		WARN_ON(h->use_count > 2);

		refcount_inc(&h->use_count);

		WARN_ON(refcount_read(&h->use_count) > 2);

		h->orig_rsv = h->block_rsv;

		h->block_rsv = NULL;

		goto got_it;
@@ -567,7 +567,7 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, 
	h->transid = cur_trans->transid;

	h->transaction = cur_trans;

	h->root = root;

	h->use_count = 1;

	refcount_set(&h->use_count, 1);

	h->fs_info = root->fs_info;



	h->type = type;
@@ -837,8 +837,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 
	int err = 0;

	int must_run_delayed_refs = 0;



	if (trans->use_count > 1) {

		trans->use_count--;

	if (refcount_read(&trans->use_count) > 1) {

		refcount_dec(&trans->use_count);

		trans->block_rsv = trans->orig_rsv;

		return 0;

	}
@@ -1868,7 +1868,7 @@ static void cleanup_transaction(struct btrfs_trans_handle *trans, 
	struct btrfs_transaction *cur_trans = trans->transaction;

	DEFINE_WAIT(wait);



	WARN_ON(trans->use_count > 1);

	WARN_ON(refcount_read(&trans->use_count) > 1);



	btrfs_abort_transaction(trans, err);

fs/btrfs/transaction.h

+1 −1
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ struct btrfs_trans_handle { 
	u64 transid;

	u64 bytes_reserved;

	u64 chunk_bytes_reserved;

	unsigned long use_count;

	refcount_t use_count;

	unsigned long delayed_ref_updates;

	struct btrfs_transaction *transaction;

	struct btrfs_block_rsv *block_rsv;