1 files changed, 95 insertions, 98 deletions

diff --git a/fs/bcachefs/debug.c b/fs/bcachefs/debug.c
index cd99b73994..ebabab171f 100644
--- a/fs/bcachefs/debug.c
+++ b/fs/bcachefs/debug.c
@@ -37,11 +37,11 @@ static bool bch2_btree_verify_replica(struct bch_fs *c, struct btree *b,
 	struct btree_node *n_ondisk = c->verify_ondisk;
 	struct btree_node *n_sorted = c->verify_data->data;
 	struct bset *sorted, *inmemory = &b->data->keys;
-	struct bch_dev *ca = bch_dev_bkey_exists(c, pick.ptr.dev);
 	struct bio *bio;
 	bool failed = false, saw_error = false;
 
-	if (!bch2_dev_get_ioref(ca, READ))
+	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	if (!ca)
 		return false;
 
 	bio = bio_alloc_bioset(ca->disk_sb.bdev,
@@ -194,8 +194,8 @@ void bch2_btree_node_ondisk_to_text(struct printbuf *out, struct bch_fs *c,
 		return;
 	}
 
-	ca = bch_dev_bkey_exists(c, pick.ptr.dev);
-	if (!bch2_dev_get_ioref(ca, READ)) {
+	ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
+	if (!ca) {
 		prt_printf(out, "error getting device to read from: not online\n");
 		return;
 	}
@@ -375,8 +375,8 @@ static ssize_t bch2_read_btree(struct file *file, char __user *buf,
 	return flush_buf(i) ?:
 		bch2_trans_run(i->c,
 			for_each_btree_key(trans, iter, i->id, i->from,
-					   BTREE_ITER_PREFETCH|
-					   BTREE_ITER_ALL_SNAPSHOTS, k, ({
+					   BTREE_ITER_prefetch|
+					   BTREE_ITER_all_snapshots, k, ({
 				bch2_bkey_val_to_text(&i->buf, i->c, k);
 				prt_newline(&i->buf);
 				bch2_trans_unlock(trans);
@@ -459,8 +459,8 @@ static ssize_t bch2_read_bfloat_failed(struct file *file, char __user *buf,
 	return flush_buf(i) ?:
 		bch2_trans_run(i->c,
 			for_each_btree_key(trans, iter, i->id, i->from,
-					   BTREE_ITER_PREFETCH|
-					   BTREE_ITER_ALL_SNAPSHOTS, k, ({
+					   BTREE_ITER_prefetch|
+					   BTREE_ITER_all_snapshots, k, ({
 				struct btree_path_level *l =
 					&btree_iter_path(trans, &iter)->l[0];
 				struct bkey_packed *_k =
@@ -492,51 +492,26 @@ static void bch2_cached_btree_node_to_text(struct printbuf *out, struct bch_fs *
 	if (!out->nr_tabstops)
 		printbuf_tabstop_push(out, 32);
 
-	prt_printf(out, "%px btree=%s l=%u ",
-	       b,
-	       bch2_btree_id_str(b->c.btree_id),
-	       b->c.level);
-	prt_newline(out);
+	prt_printf(out, "%px btree=%s l=%u\n", b, bch2_btree_id_str(b->c.btree_id), b->c.level);
 
 	printbuf_indent_add(out, 2);
 
 	bch2_bkey_val_to_text(out, c, bkey_i_to_s_c(&b->key));
 	prt_newline(out);
 
-	prt_printf(out, "flags: ");
-	prt_tab(out);
+	prt_printf(out, "flags:\t");
 	prt_bitflags(out, bch2_btree_node_flags, b->flags);
 	prt_newline(out);
 
-	prt_printf(out, "pcpu read locks: ");
-	prt_tab(out);
-	prt_printf(out, "%u", b->c.lock.readers != NULL);
-	prt_newline(out);
-
-	prt_printf(out, "written:");
-	prt_tab(out);
-	prt_printf(out, "%u", b->written);
-	prt_newline(out);
-
-	prt_printf(out, "writes blocked:");
-	prt_tab(out);
-	prt_printf(out, "%u", !list_empty_careful(&b->write_blocked));
-	prt_newline(out);
-
-	prt_printf(out, "will make reachable:");
-	prt_tab(out);
-	prt_printf(out, "%lx", b->will_make_reachable);
-	prt_newline(out);
-
-	prt_printf(out, "journal pin %px:", &b->writes[0].journal);
-	prt_tab(out);
-	prt_printf(out, "%llu", b->writes[0].journal.seq);
-	prt_newline(out);
+	prt_printf(out, "pcpu read locks:\t%u\n",	b->c.lock.readers != NULL);
+	prt_printf(out, "written:\t%u\n",		b->written);
+	prt_printf(out, "writes blocked:\t%u\n",	!list_empty_careful(&b->write_blocked));
+	prt_printf(out, "will make reachable:\t%lx\n",	b->will_make_reachable);
 
-	prt_printf(out, "journal pin %px:", &b->writes[1].journal);
-	prt_tab(out);
-	prt_printf(out, "%llu", b->writes[1].journal.seq);
-	prt_newline(out);
+	prt_printf(out, "journal pin %px:\t%llu\n",
+		   &b->writes[0].journal, b->writes[0].journal.seq);
+	prt_printf(out, "journal pin %px:\t%llu\n",
+		   &b->writes[1].journal, b->writes[1].journal.seq);
 
 	printbuf_indent_sub(out, 2);
 }
@@ -593,6 +568,32 @@ static const struct file_operations cached_btree_nodes_ops = {
 	.read		= bch2_cached_btree_nodes_read,
 };
 
+typedef int (*list_cmp_fn)(const struct list_head *l, const struct list_head *r);
+
+static void list_sort(struct list_head *head, list_cmp_fn cmp)
+{
+	struct list_head *pos;
+
+	list_for_each(pos, head)
+		while (!list_is_last(pos, head) &&
+		       cmp(pos, pos->next) > 0) {
+			struct list_head *pos2, *next = pos->next;
+
+			list_del(next);
+			list_for_each(pos2, head)
+				if (cmp(next, pos2) < 0)
+					goto pos_found;
+			BUG();
+pos_found:
+			list_add_tail(next, pos2);
+		}
+}
+
+static int list_ptr_order_cmp(const struct list_head *l, const struct list_head *r)
+{
+	return cmp_int(l, r);
+}
+
 static ssize_t bch2_btree_transactions_read(struct file *file, char __user *buf,
 					    size_t size, loff_t *ppos)
 {
@@ -600,42 +601,39 @@ static ssize_t bch2_btree_transactions_read(struct file *file, char __user *buf,
 	struct bch_fs *c = i->c;
 	struct btree_trans *trans;
 	ssize_t ret = 0;
-	u32 seq;
 
 	i->ubuf = buf;
 	i->size	= size;
 	i->ret	= 0;
 restart:
 	seqmutex_lock(&c->btree_trans_lock);
-	list_for_each_entry(trans, &c->btree_trans_list, list) {
-		struct task_struct *task = READ_ONCE(trans->locking_wait.task);
+	list_sort(&c->btree_trans_list, list_ptr_order_cmp);
 
-		if (!task || task->pid <= i->iter)
+	list_for_each_entry(trans, &c->btree_trans_list, list) {
+		if ((ulong) trans <= i->iter)
 			continue;
 
-		closure_get(&trans->ref);
-		seq = seqmutex_seq(&c->btree_trans_lock);
-		seqmutex_unlock(&c->btree_trans_lock);
+		i->iter = (ulong) trans;
 
-		ret = flush_buf(i);
-		if (ret) {
-			closure_put(&trans->ref);
-			goto unlocked;
-		}
+		if (!closure_get_not_zero(&trans->ref))
+			continue;
+
+		u32 seq = seqmutex_unlock(&c->btree_trans_lock);
 
 		bch2_btree_trans_to_text(&i->buf, trans);
 
-		prt_printf(&i->buf, "backtrace:");
-		prt_newline(&i->buf);
+		prt_printf(&i->buf, "backtrace:\n");
 		printbuf_indent_add(&i->buf, 2);
-		bch2_prt_task_backtrace(&i->buf, task, 0, GFP_KERNEL);
+		bch2_prt_task_backtrace(&i->buf, trans->locking_wait.task, 0, GFP_KERNEL);
 		printbuf_indent_sub(&i->buf, 2);
 		prt_newline(&i->buf);
 
-		i->iter = task->pid;
-
 		closure_put(&trans->ref);
 
+		ret = flush_buf(i);
+		if (ret)
+			goto unlocked;
+
 		if (!seqmutex_relock(&c->btree_trans_lock, seq))
 			goto restart;
 	}
@@ -782,25 +780,20 @@ static ssize_t btree_transaction_stats_read(struct file *file, char __user *buf,
 		    !bch2_btree_transaction_fns[i->iter])
 			break;
 
-		prt_printf(&i->buf, "%s: ", bch2_btree_transaction_fns[i->iter]);
-		prt_newline(&i->buf);
+		prt_printf(&i->buf, "%s:\n", bch2_btree_transaction_fns[i->iter]);
 		printbuf_indent_add(&i->buf, 2);
 
 		mutex_lock(&s->lock);
 
-		prt_printf(&i->buf, "Max mem used: %u", s->max_mem);
-		prt_newline(&i->buf);
-
-		prt_printf(&i->buf, "Transaction duration:");
-		prt_newline(&i->buf);
+		prt_printf(&i->buf, "Max mem used: %u\n", s->max_mem);
+		prt_printf(&i->buf, "Transaction duration:\n");
 
 		printbuf_indent_add(&i->buf, 2);
 		bch2_time_stats_to_text(&i->buf, &s->duration);
 		printbuf_indent_sub(&i->buf, 2);
 
 		if (IS_ENABLED(CONFIG_BCACHEFS_LOCK_TIME_STATS)) {
-			prt_printf(&i->buf, "Lock hold times:");
-			prt_newline(&i->buf);
+			prt_printf(&i->buf, "Lock hold times:\n");
 
 			printbuf_indent_add(&i->buf, 2);
 			bch2_time_stats_to_text(&i->buf, &s->lock_hold_times);
@@ -808,8 +801,7 @@ static ssize_t btree_transaction_stats_read(struct file *file, char __user *buf,
 		}
 
 		if (s->max_paths_text) {
-			prt_printf(&i->buf, "Maximum allocated btree paths (%u):", s->nr_max_paths);
-			prt_newline(&i->buf);
+			prt_printf(&i->buf, "Maximum allocated btree paths (%u):\n", s->nr_max_paths);
 
 			printbuf_indent_add(&i->buf, 2);
 			prt_str_indented(&i->buf, s->max_paths_text);
@@ -836,50 +828,55 @@ static const struct file_operations btree_transaction_stats_op = {
 	.read		= btree_transaction_stats_read,
 };
 
-static ssize_t bch2_btree_deadlock_read(struct file *file, char __user *buf,
-					    size_t size, loff_t *ppos)
+/* walk btree transactions until we find a deadlock and print it */
+static void btree_deadlock_to_text(struct printbuf *out, struct bch_fs *c)
 {
-	struct dump_iter *i = file->private_data;
-	struct bch_fs *c = i->c;
 	struct btree_trans *trans;
-	ssize_t ret = 0;
-	u32 seq;
-
-	i->ubuf = buf;
-	i->size	= size;
-	i->ret	= 0;
-
-	if (i->iter)
-		goto out;
+	ulong iter = 0;
 restart:
 	seqmutex_lock(&c->btree_trans_lock);
-	list_for_each_entry(trans, &c->btree_trans_list, list) {
-		struct task_struct *task = READ_ONCE(trans->locking_wait.task);
+	list_sort(&c->btree_trans_list, list_ptr_order_cmp);
 
-		if (!task || task->pid <= i->iter)
+	list_for_each_entry(trans, &c->btree_trans_list, list) {
+		if ((ulong) trans <= iter)
 			continue;
 
-		closure_get(&trans->ref);
-		seq = seqmutex_seq(&c->btree_trans_lock);
-		seqmutex_unlock(&c->btree_trans_lock);
+		iter = (ulong) trans;
 
-		ret = flush_buf(i);
-		if (ret) {
-			closure_put(&trans->ref);
-			goto out;
-		}
+		if (!closure_get_not_zero(&trans->ref))
+			continue;
 
-		bch2_check_for_deadlock(trans, &i->buf);
+		u32 seq = seqmutex_unlock(&c->btree_trans_lock);
 
-		i->iter = task->pid;
+		bool found = bch2_check_for_deadlock(trans, out) != 0;
 
 		closure_put(&trans->ref);
 
+		if (found)
+			return;
+
 		if (!seqmutex_relock(&c->btree_trans_lock, seq))
 			goto restart;
 	}
 	seqmutex_unlock(&c->btree_trans_lock);
-out:
+}
+
+static ssize_t bch2_btree_deadlock_read(struct file *file, char __user *buf,
+					    size_t size, loff_t *ppos)
+{
+	struct dump_iter *i = file->private_data;
+	struct bch_fs *c = i->c;
+	ssize_t ret = 0;
+
+	i->ubuf = buf;
+	i->size	= size;
+	i->ret	= 0;
+
+	if (!i->iter) {
+		btree_deadlock_to_text(&i->buf, c);
+		i->iter++;
+	}
+
 	if (i->buf.allocation_failure)
 		ret = -ENOMEM;