Commit 5cce1780 authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: use a negative value for BTRFS_LOG_FORCE_COMMIT 



Currently we use the value 1 for BTRFS_LOG_FORCE_COMMIT, but that value
has a few inconveniences:

1) If it's ever used by btrfs_log_inode(), or any function down the call
   chain, we have to remember to btrfs_set_log_full_commit(), which is
   repetitive and has a chance to be forgotten in future use cases.
   btrfs_log_inode_parent() only calls btrfs_set_log_full_commit() when
   it gets a negative value from btrfs_log_inode();

2) Down the call chain of btrfs_log_inode(), we may have functions that
   need to force a log commit, but can return either an error (negative
   value), false (0) or true (1). So they are forced to return some
   random negative to force a log commit - using BTRFS_LOG_FORCE_COMMIT
   would make the intention more clear. Currently the only example is
   flush_dir_items_batch().

So turn BTRFS_LOG_FORCE_COMMIT into a negative value. The chosen value
is -(MAX_ERRNO + 1), so that it does not overlap any errno value and makes
it easier to debug.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent ce394a7f

fs/btrfs/tree-log.c

+3 −7
Original line number Diff line number Diff line
@@ -3652,11 +3652,10 @@ static int flush_dir_items_batch(struct btrfs_trans_handle *trans, 


	/*

	 * If for some unexpected reason the last item's index is not greater

	 * than the last index we logged, warn and return an error to fallback

	 * to a transaction commit.

	 * than the last index we logged, warn and force a transaction commit.

	 */

	if (WARN_ON(last_index <= inode->last_dir_index_offset))

		ret = -EUCLEAN;

		ret = BTRFS_LOG_FORCE_COMMIT;

	else

		inode->last_dir_index_offset = last_index;

out:
@@ -5604,10 +5603,8 @@ static int add_conflicting_inode(struct btrfs_trans_handle *trans, 
	 * LOG_INODE_EXISTS mode) and slow down other fsyncs or transaction

	 * commits.

	 */

	if (ctx->num_conflict_inodes >= MAX_CONFLICT_INODES) {

		btrfs_set_log_full_commit(trans);

	if (ctx->num_conflict_inodes >= MAX_CONFLICT_INODES)

		return BTRFS_LOG_FORCE_COMMIT;

	}



	inode = btrfs_iget(root->fs_info->sb, ino, root);

	/*
@@ -6466,7 +6463,6 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans, 
	 * result in losing the file after a log replay.

	 */

	if (full_dir_logging && inode->last_unlink_trans >= trans->transid) {

		btrfs_set_log_full_commit(trans);

		ret = BTRFS_LOG_FORCE_COMMIT;

		goto out_unlock;

	}

fs/btrfs/tree-log.h

+7 −2
Original line number Diff line number Diff line
@@ -13,8 +13,13 @@ 
/* return value for btrfs_log_dentry_safe that means we don't need to log it at all */

#define BTRFS_NO_LOG_SYNC 256



/* We can't use the tree log for whatever reason, force a transaction commit */

#define BTRFS_LOG_FORCE_COMMIT				(1)

/*

 * We can't use the tree log for whatever reason, force a transaction commit.

 * We use a negative value because there are functions through the logging code

 * that need to return an error (< 0 value), false (0) or true (1). Any negative

 * value will do, as it will cause the log to be marked for a full sync.

 */

#define BTRFS_LOG_FORCE_COMMIT				(-(MAX_ERRNO + 1))



struct btrfs_log_ctx {

	int log_ret;