[PATCH v2] btrfs: move transaction abort message to __btrfs_abort_transaction()

[David Sterba <dsterba@suse.com>]

The btrfs_abort_transaction() is called at the location where we want to
report the abort. It must be a macro so we get the correct line and
stack trace. This inlines the necessary code and the rest is pushed to
__btrfs_abort_transaction().

There's a possibility to reduce the inlined code if we move the message
to the helper function as well, without loss of information. The
difference is only that the WARN will not print it inside the stack
report but after:

  --[ cut here ]--
  WARNING: fs/btrfs/transaction.c:2045 at btrfs_commit_transaction+0xa21/0xd30 [btrfs], CPU#11: bonnie++/3377975
  ...
  --[ end trace ] --
  BTRFS error (device dm-0 state A): Transaction aborted (error -28)

While previously there would be one more line like:

  --[ cut here ]--
  BTRFS: Transaction aborted (error -28)
  WARNING: fs/btrfs/transaction.c:2045 at btrfs_commit_transaction+0xa21/0xd30 [btrfs], CPU#11: bonnie++/3377975
  ...
  --[ end trace ] --

This removes about 20KiB of btrfs.ko on a release config.

Signed-off-by: David Sterba <dsterba@suse.com>
---

v2:
- move message in __btrfs_abort_transaction() under 'first_hit', also to
  make the WRITE_ONCE() assignments immediate
- savings updated to 20K, it depends on the config and compiler, use an
  average of a few setups

 fs/btrfs/transaction.c |  8 ++++++--
 fs/btrfs/transaction.h | 11 +----------
 2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 194f581b36f3..184fe976450e 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -2731,8 +2731,12 @@ void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 
 	WRITE_ONCE(trans->aborted, error);
 	WRITE_ONCE(trans->transaction->aborted, error);
-	if (first_hit && error == -ENOSPC)
-		btrfs_dump_space_info_for_trans_abort(fs_info);
+	if (first_hit) {
+		btrfs_err(trans->fs_info, "Transaction %llu aborted (error %d)",
+			  trans->transid, error);
+		if (error == -ENOSPC)
+			btrfs_dump_space_info_for_trans_abort(fs_info);
+	}
 	/* Wake up anybody who may be waiting on this transaction */
 	wake_up(&fs_info->transaction_wait);
 	wake_up(&fs_info->transaction_blocked_wait);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 7d70fe486758..f1cb05460cec 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -253,16 +253,7 @@ do {								\
 	if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,	\
 			&((trans)->fs_info->fs_state))) {	\
 		__first = true;					\
-		if (WARN(btrfs_abort_should_print_stack(error),	\
-			KERN_ERR				\
-			"BTRFS: Transaction aborted (error %d)\n",	\
-			(error))) {					\
-			/* Stack trace printed. */			\
-		} else {						\
-			btrfs_err((trans)->fs_info,			\
-				  "Transaction aborted (error %d)",	\
-				  (error));			\
-		}						\
+		WARN_ON(btrfs_abort_should_print_stack(error));	\
 	}							\
 	__btrfs_abort_transaction((trans), __func__,		\
 				  __LINE__, (error), __first);	\
-- 
2.53.0