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From: Kent Overstreet <kent.overstreet@linux.dev>
To: linux-bcachefs@vger.kernel.org
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Subject: [PATCH 2/9] bcachefs: Better in_restart error
Date: Sat, 26 Oct 2024 20:51:31 -0400	[thread overview]
Message-ID: <20241027005141.2337634-3-kent.overstreet@linux.dev> (raw)
In-Reply-To: <20241027005141.2337634-1-kent.overstreet@linux.dev>

We're ramping up on checking transaction restart handling correctness -
so, in debug mode we now save a backtrace for where the restart was
emitted, which makes it much easier to track down the incorrect
handling.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/btree_iter.c  | 12 ++++++++++++
 fs/bcachefs/btree_iter.h  |  4 ++++
 fs/bcachefs/btree_types.h |  3 +++
 3 files changed, 19 insertions(+)

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index b36ee4e511fa..15ac72b1af51 100644
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -1414,9 +1414,17 @@ void __noreturn bch2_trans_restart_error(struct btree_trans *trans, u32 restart_
 
 void __noreturn bch2_trans_in_restart_error(struct btree_trans *trans)
 {
+#ifdef CONFIG_BCACHEFS_DEBUG
+	struct printbuf buf = PRINTBUF;
+	bch2_prt_backtrace(&buf, &trans->last_restarted_trace);
+	panic("in transaction restart: %s, last restarted by\n%s",
+	      bch2_err_str(trans->restarted),
+	      buf.buf);
+#else
 	panic("in transaction restart: %s, last restarted by %pS\n",
 	      bch2_err_str(trans->restarted),
 	      (void *) trans->last_restarted_ip);
+#endif
 }
 
 void __noreturn bch2_trans_unlocked_error(struct btree_trans *trans)
@@ -3274,6 +3282,10 @@ void bch2_trans_put(struct btree_trans *trans)
 	closure_return_sync(&trans->ref);
 	trans->locking_wait.task = NULL;
 
+#ifdef CONFIG_BCACHEFS_DEBUG
+	darray_exit(&trans->last_restarted_trace);
+#endif
+
 	unsigned long *paths_allocated = trans->paths_allocated;
 	trans->paths_allocated	= NULL;
 	trans->paths		= NULL;
diff --git a/fs/bcachefs/btree_iter.h b/fs/bcachefs/btree_iter.h
index dda07a320488..36899c6b134e 100644
--- a/fs/bcachefs/btree_iter.h
+++ b/fs/bcachefs/btree_iter.h
@@ -350,6 +350,10 @@ static int btree_trans_restart_ip(struct btree_trans *trans, int err, unsigned l
 
 	trans->restarted = err;
 	trans->last_restarted_ip = ip;
+#ifdef CONFIG_BCACHEFS_DEBUG
+	darray_exit(&trans->last_restarted_trace);
+	bch2_save_backtrace(&trans->last_restarted_trace, current, 0, GFP_NOWAIT);
+#endif
 	return -err;
 }
 
diff --git a/fs/bcachefs/btree_types.h b/fs/bcachefs/btree_types.h
index 4568a41fefaf..baab5288ecc9 100644
--- a/fs/bcachefs/btree_types.h
+++ b/fs/bcachefs/btree_types.h
@@ -513,6 +513,9 @@ struct btree_trans {
 	u64			last_begin_time;
 	unsigned long		last_begin_ip;
 	unsigned long		last_restarted_ip;
+#ifdef CONFIG_BCACHEFS_DEBUG
+	bch_stacktrace		last_restarted_trace;
+#endif
 	unsigned long		last_unlock_ip;
 	unsigned long		srcu_lock_time;
 
-- 
2.45.2


  parent reply	other threads:[~2024-10-27  0:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-27  0:51 [PATCH 0/9] transaction restarts and other iterator work Kent Overstreet
2024-10-27  0:51 ` [PATCH 1/9] bcachefs: Assert we're not in a restart in bch2_trans_put() Kent Overstreet
2024-10-27  0:51 ` Kent Overstreet [this message]
2024-10-27  0:51 ` [PATCH 3/9] bcachefs: CONFIG_BCACHEFS_INJECT_TRANSACTION_RESTARTS Kent Overstreet
2024-10-27  0:51 ` [PATCH 4/9] bcachefs: Assert that we're not violating key cache coherency rules Kent Overstreet
2024-10-27  0:51 ` [PATCH 5/9] bcachefs: Rename btree_iter_peek_upto() -> btree_iter_peek_max() Kent Overstreet
2024-10-27  0:51 ` [PATCH 6/9] bcachefs: Simplify btree_iter_peek() filter_snapshots Kent Overstreet
2024-10-27  0:51 ` [PATCH 7/9] bcachefs: Kill unnecessary iter_rewind() in bkey_get_empty_slot() Kent Overstreet
2024-10-27  0:51 ` [PATCH 8/9] bcachefs: Implement bch2_btree_iter_prev_min() Kent Overstreet
2024-10-27  0:51 ` [PATCH 9/9] bcachefs: peek_prev_min(): Search forwards for extents, snapshots Kent Overstreet

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