bcachefs: Heap allocate printbufs

This patch changes printbufs dynamically allocate and reallocate a
buffer as needed. Stack usage has become a bit of a problem, and a major
cause of that has been static size string buffers on the stack.

The most involved part of this refactoring is that printbufs must now be
exited with printbuf_exit().

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

28 files changed, 808 insertions, 620 deletions

diff --git a/fs/bcachefs/bkey.c b/fs/bcachefs/bkey.c
index 3e62eeb6774e..a1115abf83bb 100644
--- a/fs/bcachefs/bkey.c
+++ b/fs/bcachefs/bkey.c
@@ -57,11 +57,12 @@ static void bch2_bkey_pack_verify(const struct bkey_packed *packed,
 	tmp = __bch2_bkey_unpack_key(format, packed);
 
 	if (memcmp(&tmp, unpacked, sizeof(struct bkey))) {
-		char buf1[160], buf2[160];
+		struct printbuf buf1 = PRINTBUF;
+		struct printbuf buf2 = PRINTBUF;
 		char buf3[160], buf4[160];
 
-		bch2_bkey_to_text(&PBUF(buf1), unpacked);
-		bch2_bkey_to_text(&PBUF(buf2), &tmp);
+		bch2_bkey_to_text(&buf1, unpacked);
+		bch2_bkey_to_text(&buf2, &tmp);
 		bch2_to_binary(buf3, (void *) unpacked, 80);
 		bch2_to_binary(buf4, high_word(format, packed), 80);
 
@@ -72,7 +73,7 @@ static void bch2_bkey_pack_verify(const struct bkey_packed *packed,
 		      format->bits_per_field[2],
 		      format->bits_per_field[3],
 		      format->bits_per_field[4],
-		      buf1, buf2, buf3, buf4);
+		      buf1.buf, buf2.buf, buf3, buf4);
 	}
 }
 
diff --git a/fs/bcachefs/bset.c b/fs/bcachefs/bset.c
index 58e510fa19bd..adea3cea343b 100644
--- a/fs/bcachefs/bset.c
+++ b/fs/bcachefs/bset.c
@@ -58,7 +58,7 @@ void bch2_dump_bset(struct bch_fs *c, struct btree *b,
 	struct bkey_packed *_k, *_n;
 	struct bkey uk, n;
 	struct bkey_s_c k;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 
 	if (!i->u64s)
 		return;
@@ -69,12 +69,14 @@ void bch2_dump_bset(struct bch_fs *c, struct btree *b,
 		_n = bkey_next(_k);
 
 		k = bkey_disassemble(b, _k, &uk);
+
+		printbuf_reset(&buf);
 		if (c)
-			bch2_bkey_val_to_text(&PBUF(buf), c, k);
+			bch2_bkey_val_to_text(&buf, c, k);
 		else
-			bch2_bkey_to_text(&PBUF(buf), k.k);
+			bch2_bkey_to_text(&buf, k.k);
 		printk(KERN_ERR "block %u key %5zu: %s\n", set,
-		       _k->_data - i->_data, buf);
+		       _k->_data - i->_data, buf.buf);
 
 		if (_n == vstruct_last(i))
 			continue;
@@ -90,6 +92,8 @@ void bch2_dump_bset(struct bch_fs *c, struct btree *b,
 		    !bpos_cmp(n.p, k.k->p))
 			printk(KERN_ERR "Duplicate keys\n");
 	}
+
+	printbuf_exit(&buf);
 }
 
 void bch2_dump_btree_node(struct bch_fs *c, struct btree *b)
@@ -106,6 +110,7 @@ void bch2_dump_btree_node_iter(struct btree *b,
 			      struct btree_node_iter *iter)
 {
 	struct btree_node_iter_set *set;
+	struct printbuf buf = PRINTBUF;
 
 	printk(KERN_ERR "btree node iter with %u/%u sets:\n",
 	       __btree_node_iter_used(iter), b->nsets);
@@ -114,12 +119,14 @@ void bch2_dump_btree_node_iter(struct btree *b,
 		struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 		struct bset_tree *t = bch2_bkey_to_bset(b, k);
 		struct bkey uk = bkey_unpack_key(b, k);
-		char buf[100];
 
-		bch2_bkey_to_text(&PBUF(buf), &uk);
+		printbuf_reset(&buf);
+		bch2_bkey_to_text(&buf, &uk);
 		printk(KERN_ERR "set %zu key %u: %s\n",
-		       t - b->set, set->k, buf);
+		       t - b->set, set->k, buf.buf);
 	}
+
+	printbuf_exit(&buf);
 }
 
 #ifdef CONFIG_BCACHEFS_DEBUG
@@ -155,13 +162,14 @@ static void bch2_btree_node_iter_next_check(struct btree_node_iter *_iter,
 		struct btree_node_iter_set *set;
 		struct bkey ku = bkey_unpack_key(b, k);
 		struct bkey nu = bkey_unpack_key(b, n);
-		char buf1[80], buf2[80];
+		struct printbuf buf1 = PRINTBUF;
+		struct printbuf buf2 = PRINTBUF;
 
 		bch2_dump_btree_node(NULL, b);
-		bch2_bkey_to_text(&PBUF(buf1), &ku);
-		bch2_bkey_to_text(&PBUF(buf2), &nu);
+		bch2_bkey_to_text(&buf1, &ku);
+		bch2_bkey_to_text(&buf2, &nu);
 		printk(KERN_ERR "out of order/overlapping:\n%s\n%s\n",
-		       buf1, buf2);
+		       buf1.buf, buf2.buf);
 		printk(KERN_ERR "iter was:");
 
 		btree_node_iter_for_each(_iter, set) {
@@ -226,6 +234,8 @@ void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
 	struct bset_tree *t = bch2_bkey_to_bset(b, where);
 	struct bkey_packed *prev = bch2_bkey_prev_all(b, t, where);
 	struct bkey_packed *next = (void *) (where->_data + clobber_u64s);
+	struct printbuf buf1 = PRINTBUF;
+	struct printbuf buf2 = PRINTBUF;
 #if 0
 	BUG_ON(prev &&
 	       bkey_iter_cmp(b, prev, insert) > 0);
@@ -234,17 +244,15 @@ void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
 	    bkey_iter_cmp(b, prev, insert) > 0) {
 		struct bkey k1 = bkey_unpack_key(b, prev);
 		struct bkey k2 = bkey_unpack_key(b, insert);
-		char buf1[100];
-		char buf2[100];
 
 		bch2_dump_btree_node(NULL, b);
-		bch2_bkey_to_text(&PBUF(buf1), &k1);
-		bch2_bkey_to_text(&PBUF(buf2), &k2);
+		bch2_bkey_to_text(&buf1, &k1);
+		bch2_bkey_to_text(&buf2, &k2);
 
 		panic("prev > insert:\n"
 		      "prev    key %s\n"
 		      "insert  key %s\n",
-		      buf1, buf2);
+		      buf1.buf, buf2.buf);
 	}
 #endif
 #if 0
@@ -255,17 +263,15 @@ void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
 	    bkey_iter_cmp(b, insert, next) > 0) {
 		struct bkey k1 = bkey_unpack_key(b, insert);
 		struct bkey k2 = bkey_unpack_key(b, next);
-		char buf1[100];
-		char buf2[100];
 
 		bch2_dump_btree_node(NULL, b);
-		bch2_bkey_to_text(&PBUF(buf1), &k1);
-		bch2_bkey_to_text(&PBUF(buf2), &k2);
+		bch2_bkey_to_text(&buf1, &k1);
+		bch2_bkey_to_text(&buf2, &k2);
 
 		panic("insert > next:\n"
 		      "insert  key %s\n"
 		      "next    key %s\n",
-		      buf1, buf2);
+		      buf1.buf, buf2.buf);
 	}
 #endif
 }
@@ -1555,9 +1561,6 @@ void bch2_bfloat_to_text(struct printbuf *out, struct btree *b,
 	struct bkey uk;
 	unsigned j, inorder;
 
-	if (out->pos != out->end)
-		*out->pos = '\0';
-
 	if (!bset_has_ro_aux_tree(t))
 		return;
 
diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c
index c17db1d07187..dbf3b084478f 100644
--- a/fs/bcachefs/btree_cache.c
+++ b/fs/bcachefs/btree_cache.c
@@ -742,14 +742,16 @@ static int lock_node_check_fn(struct six_lock *lock, void *p)
 
 static noinline void btree_bad_header(struct bch_fs *c, struct btree *b)
 {
-	char buf1[200], buf2[100], buf3[100];
+	struct printbuf buf1 = PRINTBUF;
+	struct printbuf buf2 = PRINTBUF;
+	struct printbuf buf3 = PRINTBUF;
 
 	if (!test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags))
 		return;
 
-	bch2_bkey_val_to_text(&PBUF(buf1), c, bkey_i_to_s_c(&b->key));
-	bch2_bpos_to_text(&PBUF(buf2), b->data->min_key);
-	bch2_bpos_to_text(&PBUF(buf3), b->data->max_key);
+	bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(&b->key));
+	bch2_bpos_to_text(&buf2, b->data->min_key);
+	bch2_bpos_to_text(&buf3, b->data->max_key);
 
 	bch2_fs_inconsistent(c, "btree node header doesn't match ptr\n"
 			     "btree %s level %u\n"
@@ -757,10 +759,14 @@ static noinline void btree_bad_header(struct bch_fs *c, struct btree *b)
 			     "header: btree %s level %llu\n"
 			     "min %s max %s\n",
 			     bch2_btree_ids[b->c.btree_id], b->c.level,
-			     buf1,
+			     buf1.buf,
 			     bch2_btree_ids[BTREE_NODE_ID(b->data)],
 			     BTREE_NODE_LEVEL(b->data),
-			     buf2, buf3);
+			     buf2.buf, buf3.buf);
+
+	printbuf_exit(&buf3);
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 }
 
 static inline void btree_check_header(struct bch_fs *c, struct btree *b)
diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index fbd54ac790ba..8eae5fb35c84 100644
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -70,23 +70,23 @@ static int bch2_gc_check_topology(struct bch_fs *c,
 	struct bpos expected_start = bkey_deleted(&prev->k->k)
 		? node_start
 		: bpos_successor(prev->k->k.p);
-	char buf1[200], buf2[200];
+	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 	int ret = 0;
 
 	if (cur.k->k.type == KEY_TYPE_btree_ptr_v2) {
 		struct bkey_i_btree_ptr_v2 *bp = bkey_i_to_btree_ptr_v2(cur.k);
 
-		if (bkey_deleted(&prev->k->k)) {
-			struct printbuf out = PBUF(buf1);
-			pr_buf(&out, "start of node: ");
-			bch2_bpos_to_text(&out, node_start);
-		} else {
-			bch2_bkey_val_to_text(&PBUF(buf1), c, bkey_i_to_s_c(prev->k));
-		}
-
 		if (bpos_cmp(expected_start, bp->v.min_key)) {
 			bch2_topology_error(c);
 
+			if (bkey_deleted(&prev->k->k)) {
+				pr_buf(&buf1, "start of node: ");
+				bch2_bpos_to_text(&buf1, node_start);
+			} else {
+				bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(prev->k));
+			}
+			bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(cur.k));
+
 			if (__fsck_err(c,
 				  FSCK_CAN_FIX|
 				  FSCK_CAN_IGNORE|
@@ -95,11 +95,11 @@ static int bch2_gc_check_topology(struct bch_fs *c,
 				  "  prev %s\n"
 				  "  cur %s",
 				  bch2_btree_ids[b->c.btree_id], b->c.level,
-				  buf1,
-				  (bch2_bkey_val_to_text(&PBUF(buf2), c, bkey_i_to_s_c(cur.k)), buf2)) &&
+				  buf1.buf, buf2.buf) &&
 			    !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
 				bch_info(c, "Halting mark and sweep to start topology repair pass");
-				return FSCK_ERR_START_TOPOLOGY_REPAIR;
+				ret = FSCK_ERR_START_TOPOLOGY_REPAIR;
+				goto err;
 			} else {
 				set_bit(BCH_FS_INITIAL_GC_UNFIXED, &c->flags);
 			}
@@ -109,6 +109,12 @@ static int bch2_gc_check_topology(struct bch_fs *c,
 	if (is_last && bpos_cmp(cur.k->k.p, node_end)) {
 		bch2_topology_error(c);
 
+		printbuf_reset(&buf1);
+		printbuf_reset(&buf2);
+
+		bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(cur.k));
+		bch2_bpos_to_text(&buf2, node_end);
+
 		if (__fsck_err(c,
 			  FSCK_CAN_FIX|
 			  FSCK_CAN_IGNORE|
@@ -117,18 +123,21 @@ static int bch2_gc_check_topology(struct bch_fs *c,
 			  "  %s\n"
 			  "  expected %s",
 			  bch2_btree_ids[b->c.btree_id], b->c.level,
-			  (bch2_bkey_val_to_text(&PBUF(buf1), c, bkey_i_to_s_c(cur.k)), buf1),
-			  (bch2_bpos_to_text(&PBUF(buf2), node_end), buf2)) &&
+			  buf1.buf, buf2.buf) &&
 		    !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
 			bch_info(c, "Halting mark and sweep to start topology repair pass");
-			return FSCK_ERR_START_TOPOLOGY_REPAIR;
+			ret = FSCK_ERR_START_TOPOLOGY_REPAIR;
+			goto err;
 		} else {
 			set_bit(BCH_FS_INITIAL_GC_UNFIXED, &c->flags);
 		}
 	}
 
 	bch2_bkey_buf_copy(prev, c, cur.k);
+err:
 fsck_err:
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 	return ret;
 }
 
@@ -251,18 +260,17 @@ static int btree_repair_node_boundaries(struct bch_fs *c, struct btree *b,
 	struct bpos expected_start = !prev
 		? b->data->min_key
 		: bpos_successor(prev->key.k.p);
-	char buf1[200], buf2[200];
+	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 	int ret = 0;
 
 	if (!prev) {
-		struct printbuf out = PBUF(buf1);
-		pr_buf(&out, "start of node: ");
-		bch2_bpos_to_text(&out, b->data->min_key);
+		pr_buf(&buf1, "start of node: ");
+		bch2_bpos_to_text(&buf1, b->data->min_key);
 	} else {
-		bch2_bkey_val_to_text(&PBUF(buf1), c, bkey_i_to_s_c(&prev->key));
+		bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(&prev->key));
 	}
 
-	bch2_bkey_val_to_text(&PBUF(buf2), c, bkey_i_to_s_c(&cur->key));
+	bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(&cur->key));
 
 	if (prev &&
 	    bpos_cmp(expected_start, cur->data->min_key) > 0 &&
@@ -275,8 +283,10 @@ static int btree_repair_node_boundaries(struct bch_fs *c, struct btree *b,
 				"  node %s\n"
 				"  next %s",
 				bch2_btree_ids[b->c.btree_id], b->c.level,
-				buf1, buf2))
-			return DROP_PREV_NODE;
+				buf1.buf, buf2.buf)) {
+			ret = DROP_PREV_NODE;
+			goto out;
+		}
 
 		if (mustfix_fsck_err_on(bpos_cmp(prev->key.k.p,
 						 bpos_predecessor(cur->data->min_key)), c,
@@ -284,7 +294,7 @@ static int btree_repair_node_boundaries(struct bch_fs *c, struct btree *b,
 				"  node %s\n"
 				"  next %s",
 				bch2_btree_ids[b->c.btree_id], b->c.level,
-				buf1, buf2))
+				buf1.buf, buf2.buf))
 			ret = set_node_max(c, prev,
 					   bpos_predecessor(cur->data->min_key));
 	} else {
@@ -296,39 +306,49 @@ static int btree_repair_node_boundaries(struct bch_fs *c, struct btree *b,
 				"  prev %s\n"
 				"  node %s",
 				bch2_btree_ids[b->c.btree_id], b->c.level,
-				buf1, buf2))
-			return DROP_THIS_NODE;
+				buf1.buf, buf2.buf)) {
+			ret = DROP_THIS_NODE;
+			goto out;
+		}
 
 		if (mustfix_fsck_err_on(bpos_cmp(expected_start, cur->data->min_key), c,
 				"btree node with incorrect min_key at btree %s level %u:\n"
 				"  prev %s\n"
 				"  node %s",
 				bch2_btree_ids[b->c.btree_id], b->c.level,
-				buf1, buf2))
+				buf1.buf, buf2.buf))
 		    ret = set_node_min(c, cur, expected_start);
 	}
+out:
 fsck_err:
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 	return ret;
 }
 
 static int btree_repair_node_end(struct bch_fs *c, struct btree *b,
 				 struct btree *child)
 {
-	char buf1[200], buf2[200];
+	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 	int ret = 0;
 
+	bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(&child->key));
+	bch2_bpos_to_text(&buf2, b->key.k.p);
+
 	if (mustfix_fsck_err_on(bpos_cmp(child->key.k.p, b->key.k.p), c,
 			"btree node with incorrect max_key at btree %s level %u:\n"
 			"  %s\n"
 			"  expected %s",
 			bch2_btree_ids[b->c.btree_id], b->c.level,
-			(bch2_bkey_val_to_text(&PBUF(buf1), c, bkey_i_to_s_c(&child->key)), buf1),
-			(bch2_bpos_to_text(&PBUF(buf2), b->key.k.p), buf2))) {
+			buf1.buf, buf2.buf)) {
 		ret = set_node_max(c, child, b->key.k.p);
 		if (ret)
-			return ret;
+			goto err;
 	}
+err:
 fsck_err:
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 	return ret;
 }
 
@@ -339,7 +359,7 @@ static int bch2_btree_repair_topology_recurse(struct bch_fs *c, struct btree *b)
 	struct bkey_buf prev_k, cur_k;
 	struct btree *prev = NULL, *cur = NULL;
 	bool have_child, dropped_children = false;
-	char buf[200];
+	struct printbuf buf;
 	int ret = 0;
 
 	if (!b->c.level)
@@ -363,12 +383,15 @@ again:
 					false);
 		ret = PTR_ERR_OR_ZERO(cur);
 
+		printbuf_reset(&buf);
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(cur_k.k));
+
 		if (mustfix_fsck_err_on(ret == -EIO, c,
 				"Unreadable btree node at btree %s level %u:\n"
 				"  %s",
 				bch2_btree_ids[b->c.btree_id],
 				b->c.level - 1,
-				(bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(cur_k.k)), buf))) {
+				buf.buf)) {
 			bch2_btree_node_evict(c, cur_k.k);
 			ret = bch2_journal_key_delete(c, b->c.btree_id,
 						      b->c.level, cur_k.k->k.p);
@@ -468,12 +491,14 @@ again:
 		have_child = true;
 	}
 
+	printbuf_reset(&buf);
+	bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
+
 	if (mustfix_fsck_err_on(!have_child, c,
 			"empty interior btree node at btree %s level %u\n"
 			"  %s",
 			bch2_btree_ids[b->c.btree_id],
-			b->c.level,
-			(bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(&b->key)), buf)))
+			b->c.level, buf.buf))
 		ret = DROP_THIS_NODE;
 err:
 fsck_err:
@@ -489,6 +514,7 @@ fsck_err:
 	if (!ret && dropped_children)
 		goto again;
 
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -524,7 +550,7 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 	const union bch_extent_entry *entry;
 	struct extent_ptr_decoded p = { 0 };
 	bool do_update = false;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	/*
@@ -542,7 +568,8 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 				p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 				bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 				p.ptr.gen,
-				(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf))) {
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, *k), buf.buf))) {
 			if (!p.ptr.cached) {
 				g->_mark.gen		= p.ptr.gen;
 				g->gen_valid		= true;
@@ -557,7 +584,8 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 				p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 				bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 				p.ptr.gen, g->mark.gen,
-				(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf))) {
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, *k), buf.buf))) {
 			if (!p.ptr.cached) {
 				g->_mark.gen		= p.ptr.gen;
 				g->gen_valid		= true;
@@ -576,7 +604,8 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 				p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr), g->mark.gen,
 				bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 				p.ptr.gen,
-				(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf)))
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 			do_update = true;
 
 		if (fsck_err_on(!p.ptr.cached &&
@@ -586,7 +615,8 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 				p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 				bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 				p.ptr.gen, g->mark.gen,
-				(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf)))
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 			do_update = true;
 
 		if (data_type != BCH_DATA_btree && p.ptr.gen != g->mark.gen)
@@ -599,7 +629,8 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 				p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 				bch2_data_types[g->mark.data_type],
 				bch2_data_types[data_type],
-				(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf))) {
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, *k), buf.buf))) {
 			if (data_type == BCH_DATA_btree) {
 				g->_mark.data_type	= data_type;
 				set_bit(BCH_FS_NEED_ANOTHER_GC, &c->flags);
@@ -615,14 +646,16 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 					"pointer to nonexistent stripe %llu\n"
 					"while marking %s",
 					(u64) p.ec.idx,
-					(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf)))
+					(printbuf_reset(&buf),
+					 bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 				do_update = true;
 
 			if (fsck_err_on(!bch2_ptr_matches_stripe_m(m, p), c,
 					"pointer does not match stripe %llu\n"
 					"while marking %s",
 					(u64) p.ec.idx,
-					(bch2_bkey_val_to_text(&PBUF(buf), c, *k), buf)))
+					(printbuf_reset(&buf),
+					 bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 				do_update = true;
 		}
 	}
@@ -635,13 +668,15 @@ static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
 
 		if (is_root) {
 			bch_err(c, "cannot update btree roots yet");
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err;
 		}
 
 		new = kmalloc(bkey_bytes(k->k), GFP_KERNEL);
 		if (!new) {
 			bch_err(c, "%s: error allocating new key", __func__);
-			return -ENOMEM;
+			ret = -ENOMEM;
+			goto err;
 		}
 
 		bkey_reassemble(new, *k);
@@ -705,19 +740,25 @@ found:
 		ret = bch2_journal_key_insert_take(c, btree_id, level, new);
 		if (ret) {
 			kfree(new);
-			return ret;
+			goto err;
 		}
 
 		if (level)
 			bch2_btree_node_update_key_early(c, btree_id, level - 1, *k, new);
 
-		bch2_bkey_val_to_text(&PBUF(buf), c, *k);
-		bch_info(c, "updated %s", buf);
-		bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(new));
-		bch_info(c, "new key %s", buf);
+		printbuf_reset(&buf);
+		bch2_bkey_val_to_text(&buf, c, *k);
+		bch_info(c, "updated %s", buf.buf);
+
+		printbuf_reset(&buf);
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(new));
+		bch_info(c, "new key %s", buf.buf);
+
 		*k = bkey_i_to_s_c(new);
 	}
+err:
 fsck_err:
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -852,7 +893,7 @@ static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b
 	struct btree_and_journal_iter iter;
 	struct bkey_s_c k;
 	struct bkey_buf cur, prev;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
@@ -913,7 +954,8 @@ static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b
 					  "  %s",
 					  bch2_btree_ids[b->c.btree_id],
 					  b->c.level - 1,
-					  (bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(cur.k)), buf)) &&
+					  (printbuf_reset(&buf),
+					   bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(cur.k)), buf.buf)) &&
 				    !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
 					ret = FSCK_ERR_START_TOPOLOGY_REPAIR;
 					bch_info(c, "Halting mark and sweep to start topology repair pass");
@@ -943,6 +985,7 @@ fsck_err:
 	bch2_bkey_buf_exit(&cur, c);
 	bch2_bkey_buf_exit(&prev, c);
 	bch2_btree_and_journal_iter_exit(&iter);
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -956,7 +999,7 @@ static int bch2_gc_btree_init(struct btree_trans *trans,
 		: bch2_expensive_debug_checks		? 0
 		: !btree_node_type_needs_gc(btree_id)	? 1
 		: 0;
-	char buf[100];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	b = c->btree_roots[btree_id].b;
@@ -965,17 +1008,19 @@ static int bch2_gc_btree_init(struct btree_trans *trans,
 		return 0;
 
 	six_lock_read(&b->c.lock, NULL, NULL);
+	printbuf_reset(&buf);
+	bch2_bpos_to_text(&buf, b->data->min_key);
 	if (mustfix_fsck_err_on(bpos_cmp(b->data->min_key, POS_MIN), c,
-			"btree root with incorrect min_key: %s",
-			(bch2_bpos_to_text(&PBUF(buf), b->data->min_key), buf))) {
+			"btree root with incorrect min_key: %s", buf.buf)) {
 		bch_err(c, "repair unimplemented");
 		ret = FSCK_ERR_EXIT;
 		goto fsck_err;
 	}
 
+	printbuf_reset(&buf);
+	bch2_bpos_to_text(&buf, b->data->max_key);
 	if (mustfix_fsck_err_on(bpos_cmp(b->data->max_key, SPOS_MAX), c,
-			"btree root with incorrect max_key: %s",
-			(bch2_bpos_to_text(&PBUF(buf), b->data->max_key), buf))) {
+			"btree root with incorrect max_key: %s", buf.buf)) {
 		bch_err(c, "repair unimplemented");
 		ret = FSCK_ERR_EXIT;
 		goto fsck_err;
@@ -995,6 +1040,7 @@ fsck_err:
 
 	if (ret < 0)
 		bch_err(c, "%s: ret %i", __func__, ret);
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -1131,6 +1177,7 @@ static int bch2_gc_done(struct bch_fs *c,
 			bool initial, bool metadata_only)
 {
 	struct bch_dev *ca = NULL;
+	struct printbuf buf = PRINTBUF;
 	bool verify = !metadata_only && (!initial ||
 		       (c->sb.compat & (1ULL << BCH_COMPAT_alloc_info)));
 	unsigned i, dev;
@@ -1201,16 +1248,16 @@ static int bch2_gc_done(struct bch_fs *c,
 		for (i = 0; i < c->replicas.nr; i++) {
 			struct bch_replicas_entry *e =
 				cpu_replicas_entry(&c->replicas, i);
-			char buf[80];
 
 			if (metadata_only &&
 			    (e->data_type == BCH_DATA_user ||
 			     e->data_type == BCH_DATA_cached))
 				continue;
 
-			bch2_replicas_entry_to_text(&PBUF(buf), e);
+			printbuf_reset(&buf);
+			bch2_replicas_entry_to_text(&buf, e);
 
-			copy_fs_field(replicas[i], "%s", buf);
+			copy_fs_field(replicas[i], "%s", buf.buf);
 		}
 	}
 
@@ -1225,6 +1272,7 @@ fsck_err:
 		bch_err(c, "%s: ret %i", __func__, ret);
 
 	percpu_up_write(&c->mark_lock);
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -1424,7 +1472,7 @@ static int bch2_gc_reflink_done(struct bch_fs *c, bool metadata_only)
 	struct bkey_s_c k;
 	struct reflink_gc *r;
 	size_t idx = 0;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	if (metadata_only)
@@ -1452,7 +1500,8 @@ static int bch2_gc_reflink_done(struct bch_fs *c, bool metadata_only)
 				"reflink key has wrong refcount:\n"
 				"  %s\n"
 				"  should be %u",
-				(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf),
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, k), buf.buf),
 				r->refcount)) {
 			struct bkey_i *new;
 
@@ -1481,6 +1530,7 @@ fsck_err:
 	bch2_trans_iter_exit(&trans, &iter);
 	c->reflink_gc_nr = 0;
 	bch2_trans_exit(&trans);
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -1539,7 +1589,7 @@ static int bch2_gc_stripes_done(struct bch_fs *c, bool metadata_only)
 	struct bkey_s_c k;
 	struct gc_stripe *m;
 	const struct bch_stripe *s;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	unsigned i;
 	int ret = 0;
 
@@ -1565,7 +1615,8 @@ inconsistent:
 				"stripe has wrong block sector count %u:\n"
 				"  %s\n"
 				"  should be %u", i,
-				(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf),
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, k), buf.buf),
 				m ? m->block_sectors[i] : 0)) {
 			struct bkey_i_stripe *new;
 
@@ -1589,6 +1640,8 @@ fsck_err:
 	bch2_trans_iter_exit(&trans, &iter);
 
 	bch2_trans_exit(&trans);
+
+	printbuf_exit(&buf);
 	return ret;
 }
 
diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index c65c640753b6..1dc21b5948ea 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -534,13 +534,7 @@ enum btree_validate_ret {
 #define btree_err(type, c, ca, b, i, msg, ...)				\
 ({									\
 	__label__ out;							\
-	char _buf[300];							\
-	char *_buf2 = _buf;						\
-	struct printbuf out = PBUF(_buf);				\
-									\
-	_buf2 = kmalloc(4096, GFP_ATOMIC);				\
-	if (_buf2)							\
-		out = _PBUF(_buf2, 4986);				\
+	struct printbuf out = PRINTBUF;					\
 									\
 	btree_err_msg(&out, c, ca, b, i, b->written, write);		\
 	pr_buf(&out, ": " msg, ##__VA_ARGS__);				\
@@ -548,14 +542,13 @@ enum btree_validate_ret {
 	if (type == BTREE_ERR_FIXABLE &&				\
 	    write == READ &&						\
 	    !test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags)) {		\
-		mustfix_fsck_err(c, "%s", _buf2);			\
+		mustfix_fsck_err(c, "%s", out.buf);			\
 		goto out;						\
 	}								\
 									\
 	switch (write) {						\
 	case READ:							\
-		if (_buf2)						\
-			bch_err(c, "%s", _buf2);			\
+		bch_err(c, "%s", out.buf);				\
 									\
 		switch (type) {						\
 		case BTREE_ERR_FIXABLE:					\
@@ -576,7 +569,7 @@ enum btree_validate_ret {
 		}							\
 		break;							\
 	case WRITE:							\
-		bch_err(c, "corrupt metadata before write: %s", _buf2);	\
+		bch_err(c, "corrupt metadata before write: %s", out.buf);\
 									\
 		if (bch2_fs_inconsistent(c)) {				\
 			ret = BCH_FSCK_ERRORS_NOT_FIXED;		\
@@ -585,8 +578,7 @@ enum btree_validate_ret {
 		break;							\
 	}								\
 out:									\
-	if (_buf2 != _buf)						\
-		kfree(_buf2);						\
+	printbuf_exit(&out);						\
 	true;								\
 })
 
@@ -648,8 +640,8 @@ static int validate_bset(struct bch_fs *c, struct bch_dev *ca,
 {
 	unsigned version = le16_to_cpu(i->version);
 	const char *err;
-	char buf1[100];
-	char buf2[100];
+	struct printbuf buf1 = PRINTBUF;
+	struct printbuf buf2 = PRINTBUF;
 	int ret = 0;
 
 	btree_err_on((version != BCH_BSET_VERSION_OLD &&
@@ -686,7 +678,8 @@ static int validate_bset(struct bch_fs *c, struct bch_dev *ca,
 			 BTREE_ERR_FIXABLE, c, ca, b, i,
 			 "bset past end of btree node")) {
 		i->u64s = 0;
-		return 0;
+		ret = 0;
+		goto out;
 	}
 
 	btree_err_on(offset && !i->u64s,
@@ -737,14 +730,17 @@ static int validate_bset(struct bch_fs *c, struct bch_dev *ca,
 			btree_err_on(bpos_cmp(b->data->min_key, bp->min_key),
 				     BTREE_ERR_MUST_RETRY, c, ca, b, NULL,
 				     "incorrect min_key: got %s should be %s",
-				     (bch2_bpos_to_text(&PBUF(buf1), bn->min_key), buf1),
-				     (bch2_bpos_to_text(&PBUF(buf2), bp->min_key), buf2));
+				     (printbuf_reset(&buf1),
+				      bch2_bpos_to_text(&buf1, bn->min_key), buf1.buf),
+				     (printbuf_reset(&buf2),
+				      bch2_bpos_to_text(&buf2, bp->min_key), buf2.buf));
 		}
 
 		btree_err_on(bpos_cmp(bn->max_key, b->key.k.p),
 			     BTREE_ERR_MUST_RETRY, c, ca, b, i,
 			     "incorrect max key %s",
-			     (bch2_bpos_to_text(&PBUF(buf1), bn->max_key), buf1));
+			     (printbuf_reset(&buf1),
+			      bch2_bpos_to_text(&buf1, bn->max_key), buf1.buf));
 
 		if (write)
 			compat_btree_node(b->c.level, b->c.btree_id, version,
@@ -759,7 +755,10 @@ static int validate_bset(struct bch_fs *c, struct bch_dev *ca,
 			       BSET_BIG_ENDIAN(i), write,
 			       &bn->format);
 	}
+out:
 fsck_err:
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 	return ret;
 }
 
@@ -769,6 +768,8 @@ static int validate_bset_keys(struct bch_fs *c, struct btree *b,
 {
 	unsigned version = le16_to_cpu(i->version);
 	struct bkey_packed *k, *prev = NULL;
+	struct printbuf buf1 = PRINTBUF;
+	struct printbuf buf2 = PRINTBUF;
 	bool updated_range = b->key.k.type == KEY_TYPE_btree_ptr_v2 &&
 		BTREE_PTR_RANGE_UPDATED(&bkey_i_to_btree_ptr_v2(&b->key)->v);
 	int ret = 0;
@@ -807,11 +808,10 @@ static int validate_bset_keys(struct bch_fs *c, struct btree *b,
 			(!updated_range ?  bch2_bkey_in_btree_node(b, u.s_c) : NULL) ?:
 			(write ? bch2_bkey_val_invalid(c, u.s_c) : NULL);
 		if (invalid) {
-			char buf[160];
-
-			bch2_bkey_val_to_text(&PBUF(buf), c, u.s_c);
+			printbuf_reset(&buf1);
+			bch2_bkey_val_to_text(&buf1, c, u.s_c);
 			btree_err(BTREE_ERR_FIXABLE, c, NULL, b, i,
-				  "invalid bkey: %s\n%s", invalid, buf);
+				  "invalid bkey: %s\n%s", invalid, buf1.buf);
 
 			i->u64s = cpu_to_le16(le16_to_cpu(i->u64s) - k->u64s);
 			memmove_u64s_down(k, bkey_next(k),
@@ -825,18 +825,18 @@ static int validate_bset_keys(struct bch_fs *c, struct btree *b,
 				    &b->format, k);
 
 		if (prev && bkey_iter_cmp(b, prev, k) > 0) {
-			char buf1[80];
-			char buf2[80];
 			struct bkey up = bkey_unpack_key(b, prev);
 
-			bch2_bkey_to_text(&PBUF(buf1), &up);
-			bch2_bkey_to_text(&PBUF(buf2), u.k);
+			printbuf_reset(&buf1);
+			bch2_bkey_to_text(&buf1, &up);
+			printbuf_reset(&buf2);
+			bch2_bkey_to_text(&buf2, u.k);
 
 			bch2_dump_bset(c, b, i, 0);
 
 			if (btree_err(BTREE_ERR_FIXABLE, c, NULL, b, i,
 				      "keys out of order: %s > %s",
-				      buf1, buf2)) {
+				      buf1.buf, buf2.buf)) {
 				i->u64s = cpu_to_le16(le16_to_cpu(i->u64s) - k->u64s);
 				memmove_u64s_down(k, bkey_next(k),
 						  (u64 *) vstruct_end(i) - (u64 *) k);
@@ -848,6 +848,8 @@ static int validate_bset_keys(struct bch_fs *c, struct btree *b,
 		k = bkey_next(k);
 	}
 fsck_err:
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 	return ret;
 }
 
@@ -1063,11 +1065,12 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 		if (invalid ||
 		    (bch2_inject_invalid_keys &&
 		     !bversion_cmp(u.k->version, MAX_VERSION))) {
-			char buf[160];
+			struct printbuf buf = PRINTBUF;
 
-			bch2_bkey_val_to_text(&PBUF(buf), c, u.s_c);
+			bch2_bkey_val_to_text(&buf, c, u.s_c);
 			btree_err(BTREE_ERR_FIXABLE, c, NULL, b, i,
 				  "invalid bkey %s: %s", buf, invalid);
+			printbuf_exit(&buf);
 
 			btree_keys_account_key_drop(&b->nr, 0, k);
 
@@ -1124,8 +1127,7 @@ static void btree_node_read_work(struct work_struct *work)
 	struct bch_dev *ca	= bch_dev_bkey_exists(c, rb->pick.ptr.dev);
 	struct bio *bio		= &rb->bio;
 	struct bch_io_failures failed = { .nr = 0 };
-	char buf[200];
-	struct printbuf out;
+	struct printbuf buf = PRINTBUF;
 	bool saw_error = false;
 	bool can_retry;
 
@@ -1145,10 +1147,10 @@ static void btree_node_read_work(struct work_struct *work)
 			bio->bi_status = BLK_STS_REMOVED;
 		}
 start:
-		out = PBUF(buf);
-		btree_pos_to_text(&out, c, b);
+		printbuf_reset(&buf);
+		btree_pos_to_text(&buf, c, b);
 		bch2_dev_io_err_on(bio->bi_status, ca, "btree read error %s for %s",
-				   bch2_blk_status_to_str(bio->bi_status), buf);
+				   bch2_blk_status_to_str(bio->bi_status), buf.buf);
 		if (rb->have_ioref)
 			percpu_ref_put(&ca->io_ref);
 		rb->have_ioref = false;
@@ -1174,6 +1176,7 @@ start:
 	bch2_time_stats_update(&c->times[BCH_TIME_btree_node_read],
 			       rb->start_time);
 	bio_put(&rb->bio);
+	printbuf_exit(&buf);
 
 	if (saw_error && !btree_node_read_error(b))
 		bch2_btree_node_rewrite_async(c, b);
@@ -1254,6 +1257,7 @@ static void btree_node_read_all_replicas_done(struct closure *cl)
 		container_of(cl, struct btree_node_read_all, cl);
 	struct bch_fs *c = ra->c;
 	struct btree *b = ra->b;
+	struct printbuf buf = PRINTBUF;
 	bool dump_bset_maps = false;
 	bool have_retry = false;
 	int ret = 0, best = -1, write = READ;
@@ -1297,8 +1301,6 @@ static void btree_node_read_all_replicas_done(struct closure *cl)
 fsck_err:
 	if (dump_bset_maps) {
 		for (i = 0; i < ra->nr; i++) {
-			char buf[200];
-			struct printbuf out = PBUF(buf);
 			struct btree_node *bn = ra->buf[i];
 			struct btree_node_entry *bne = NULL;
 			unsigned offset = 0, sectors;
@@ -1307,6 +1309,8 @@ fsck_err:
 			if (ra->err[i])
 				continue;
 
+			printbuf_reset(&buf);
+
 			while (offset < btree_sectors(c)) {
 				if (!offset) {
 					sectors = vstruct_sectors(bn, c->block_bits);
@@ -1317,10 +1321,10 @@ fsck_err:
 					sectors = vstruct_sectors(bne, c->block_bits);
 				}
 
-				pr_buf(&out, " %u-%u", offset, offset + sectors);
+				pr_buf(&buf, " %u-%u", offset, offset + sectors);
 				if (bne && bch2_journal_seq_is_blacklisted(c,
 							le64_to_cpu(bne->keys.journal_seq), false))
-					pr_buf(&out, "*");
+					pr_buf(&buf, "*");
 				offset += sectors;
 			}
 
@@ -1328,19 +1332,19 @@ fsck_err:
 				bne = ra->buf[i] + (offset << 9);
 				if (bne->keys.seq == bn->keys.seq) {
 					if (!gap)
-						pr_buf(&out, " GAP");
+						pr_buf(&buf, " GAP");
 					gap = true;
 
 					sectors = vstruct_sectors(bne, c->block_bits);
-					pr_buf(&out, " %u-%u", offset, offset + sectors);
+					pr_buf(&buf, " %u-%u", offset, offset + sectors);
 					if (bch2_journal_seq_is_blacklisted(c,
 							le64_to_cpu(bne->keys.journal_seq), false))
-						pr_buf(&out, "*");
+						pr_buf(&buf, "*");
 				}
 				offset++;
 			}
 
-			bch_err(c, "replica %u:%s", i, buf);
+			bch_err(c, "replica %u:%s", i, buf.buf);
 		}
 	}
 
@@ -1361,6 +1365,7 @@ fsck_err:
 
 	closure_debug_destroy(&ra->cl);
 	kfree(ra);
+	printbuf_exit(&buf);
 
 	clear_btree_node_read_in_flight(b);
 	wake_up_bit(&b->flags, BTREE_NODE_read_in_flight);
@@ -1461,23 +1466,23 @@ void bch2_btree_node_read(struct bch_fs *c, struct btree *b,
 	struct btree_read_bio *rb;
 	struct bch_dev *ca;
 	struct bio *bio;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret;
 
-	btree_pos_to_text(&PBUF(buf), c, b);
+	btree_pos_to_text(&buf, c, b);
 	trace_btree_read(c, b);
 
 	if (bch2_verify_all_btree_replicas &&
 	    !btree_node_read_all_replicas(c, b, sync))
-		return;
+		goto out;
 
 	ret = bch2_bkey_pick_read_device(c, bkey_i_to_s_c(&b->key),
 					 NULL, &pick);
 	if (bch2_fs_fatal_err_on(ret <= 0, c,
 			"btree node read error: no device to read from\n"
-			" at %s", buf)) {
+			" at %s", buf.buf)) {
 		set_btree_node_read_error(b);
-		return;
+		goto out;
 	}
 
 	ca = bch_dev_bkey_exists(c, pick.ptr.dev);
@@ -1519,6 +1524,8 @@ void bch2_btree_node_read(struct bch_fs *c, struct btree *b,
 		else
 			queue_work(c->io_complete_wq, &rb->work);
 	}
+out:
+	printbuf_exit(&buf);
 }
 
 int bch2_btree_root_read(struct bch_fs *c, enum btree_id id,
diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index b58219292f34..92258281fdc7 100644
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -574,7 +574,9 @@ static void bch2_btree_path_verify_level(struct btree_trans *trans,
 	struct btree_node_iter tmp;
 	bool locked;
 	struct bkey_packed *p, *k;
-	char buf1[100], buf2[100], buf3[100];
+	struct printbuf buf1 = PRINTBUF;
+	struct printbuf buf2 = PRINTBUF;
+	struct printbuf buf3 = PRINTBUF;
 	const char *msg;
 
 	if (!bch2_debug_check_iterators)
@@ -622,26 +624,27 @@ static void bch2_btree_path_verify_level(struct btree_trans *trans,
 		btree_node_unlock(path, level);
 	return;
 err:
-	strcpy(buf2, "(none)");
-	strcpy(buf3, "(none)");
-
-	bch2_bpos_to_text(&PBUF(buf1), path->pos);
+	bch2_bpos_to_text(&buf1, path->pos);
 
 	if (p) {
 		struct bkey uk = bkey_unpack_key(l->b, p);
-		bch2_bkey_to_text(&PBUF(buf2), &uk);
+		bch2_bkey_to_text(&buf2, &uk);
+	} else {
+		pr_buf(&buf2, "(none)");
 	}
 
 	if (k) {
 		struct bkey uk = bkey_unpack_key(l->b, k);
-		bch2_bkey_to_text(&PBUF(buf3), &uk);
+		bch2_bkey_to_text(&buf3, &uk);
+	} else {
+		pr_buf(&buf3, "(none)");
 	}
 
 	panic("path should be %s key at level %u:\n"
 	      "path pos %s\n"
 	      "prev key %s\n"
 	      "cur  key %s\n",
-	      msg, level, buf1, buf2, buf3);
+	      msg, level, buf1.buf, buf2.buf, buf3.buf);
 }
 
 static void bch2_btree_path_verify(struct btree_trans *trans,
@@ -739,16 +742,16 @@ static int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k
 	if (!bkey_cmp(prev.k->p, k.k->p) &&
 	    bch2_snapshot_is_ancestor(trans->c, iter->snapshot,
 				      prev.k->p.snapshot) > 0) {
-		char buf1[100], buf2[200];
+		struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
-		bch2_bkey_to_text(&PBUF(buf1), k.k);
-		bch2_bkey_to_text(&PBUF(buf2), prev.k);
+		bch2_bkey_to_text(&buf1, k.k);
+		bch2_bkey_to_text(&buf2, prev.k);
 
 		panic("iter snap %u\n"
 		      "k    %s\n"
 		      "prev %s\n",
 		      iter->snapshot,
-		      buf1, buf2);
+		      buf1.buf, buf2.buf);
 	}
 out:
 	bch2_trans_iter_exit(trans, &copy);
@@ -760,7 +763,7 @@ void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
 {
 	struct btree_path *path;
 	unsigned idx;
-	char buf[100];
+	struct printbuf buf = PRINTBUF;
 
 	trans_for_each_path_inorder(trans, path, idx) {
 		int cmp = cmp_int(path->btree_id, id) ?:
@@ -786,9 +789,10 @@ void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
 	}
 
 	bch2_dump_trans_paths_updates(trans);
+	bch2_bpos_to_text(&buf, pos);
+
 	panic("not locked: %s %s%s\n",
-	      bch2_btree_ids[id],
-	      (bch2_bpos_to_text(&PBUF(buf), pos), buf),
+	      bch2_btree_ids[id], buf.buf,
 	      key_cache ? " cached" : "");
 }
 
@@ -1071,23 +1075,23 @@ static void btree_path_verify_new_node(struct btree_trans *trans,
 	if (!k ||
 	    bkey_deleted(k) ||
 	    bkey_cmp_left_packed(l->b, k, &b->key.k.p)) {
-		char buf1[100];
-		char buf2[100];
-		char buf3[100];
-		char buf4[100];
+		struct printbuf buf1 = PRINTBUF;
+		struct printbuf buf2 = PRINTBUF;
+		struct printbuf buf3 = PRINTBUF;
+		struct printbuf buf4 = PRINTBUF;
 		struct bkey uk = bkey_unpack_key(b, k);
 
 		bch2_dump_btree_node(c, l->b);
-		bch2_bpos_to_text(&PBUF(buf1), path->pos);
-		bch2_bkey_to_text(&PBUF(buf2), &uk);
-		bch2_bpos_to_text(&PBUF(buf3), b->data->min_key);
-		bch2_bpos_to_text(&PBUF(buf3), b->data->max_key);
+		bch2_bpos_to_text(&buf1, path->pos);
+		bch2_bkey_to_text(&buf2, &uk);
+		bch2_bpos_to_text(&buf3, b->data->min_key);
+		bch2_bpos_to_text(&buf3, b->data->max_key);
 		panic("parent iter doesn't point to new node:\n"
 		      "iter pos %s %s\n"
 		      "iter key %s\n"
 		      "new node %s-%s\n",
-		      bch2_btree_ids[path->btree_id], buf1,
-		      buf2, buf3, buf4);
+		      bch2_btree_ids[path->btree_id],
+		      buf1.buf, buf2.buf, buf3.buf, buf4.buf);
 	}
 
 	if (!parent_locked)
@@ -1783,18 +1787,22 @@ void bch2_dump_trans_paths_updates(struct btree_trans *trans)
 {
 	struct btree_path *path;
 	struct btree_insert_entry *i;
+	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 	unsigned idx;
-	char buf1[300], buf2[300];
 
 	btree_trans_sort_paths(trans);
 
-	trans_for_each_path_inorder(trans, path, idx)
+	trans_for_each_path_inorder(trans, path, idx) {
+		printbuf_reset(&buf1);
+
+		bch2_bpos_to_text(&buf1, path->pos);
+
 		printk(KERN_ERR "path: idx %u ref %u:%u%s%s btree %s pos %s locks %u %pS\n",
 		       path->idx, path->ref, path->intent_ref,
 		       path->should_be_locked ? " S" : "",
 		       path->preserve ? " P" : "",
 		       bch2_btree_ids[path->btree_id],
-		       (bch2_bpos_to_text(&PBUF(buf1), path->pos), buf1),
+		       buf1.buf,
 		       path->nodes_locked,
 #ifdef CONFIG_BCACHEFS_DEBUG
 		       (void *) path->ip_allocated
@@ -1802,17 +1810,25 @@ void bch2_dump_trans_paths_updates(struct btree_trans *trans)
 		       NULL
 #endif
 		       );
+	}
 
 	trans_for_each_update(trans, i) {
 		struct bkey u;
 		struct bkey_s_c old = bch2_btree_path_peek_slot(i->path, &u);
 
+		printbuf_reset(&buf1);
+		printbuf_reset(&buf2);
+		bch2_bkey_val_to_text(&buf1, trans->c, old);
+		bch2_bkey_val_to_text(&buf2, trans->c, bkey_i_to_s_c(i->k));
+
 		printk(KERN_ERR "update: btree %s %pS\n  old %s\n  new %s",
 		       bch2_btree_ids[i->btree_id],
 		       (void *) i->ip_allocated,
-		       (bch2_bkey_val_to_text(&PBUF(buf1), trans->c, old), buf1),
-		       (bch2_bkey_val_to_text(&PBUF(buf2), trans->c, bkey_i_to_s_c(i->k)), buf2));
+		       buf1.buf, buf2.buf);
 	}
+
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 }
 
 static struct btree_path *btree_path_alloc(struct btree_trans *trans,
diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index 255753b2dc0e..ed0a70f7ea68 100644
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -41,7 +41,7 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
 	struct bkey_s_c k;
 	struct bkey_s_c_btree_ptr_v2 bp;
 	struct bkey unpacked;
-	char buf1[100], buf2[100];
+	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
 	BUG_ON(!b->c.level);
 
@@ -58,9 +58,9 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
 
 		if (bpos_cmp(next_node, bp.v->min_key)) {
 			bch2_dump_btree_node(c, b);
-			panic("expected next min_key %s got %s\n",
-			      (bch2_bpos_to_text(&PBUF(buf1), next_node), buf1),
-			      (bch2_bpos_to_text(&PBUF(buf2), bp.v->min_key), buf2));
+			bch2_bpos_to_text(&buf1, next_node);
+			bch2_bpos_to_text(&buf2, bp.v->min_key);
+			panic("expected next min_key %s got %s\n", buf1.buf, buf2.buf);
 		}
 
 		bch2_btree_node_iter_advance(&iter, b);
@@ -68,9 +68,9 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
 		if (bch2_btree_node_iter_end(&iter)) {
 			if (bpos_cmp(k.k->p, b->key.k.p)) {
 				bch2_dump_btree_node(c, b);
-				panic("expected end %s got %s\n",
-				      (bch2_bpos_to_text(&PBUF(buf1), b->key.k.p), buf1),
-				      (bch2_bpos_to_text(&PBUF(buf2), k.k->p), buf2));
+				bch2_bpos_to_text(&buf1, b->key.k.p);
+				bch2_bpos_to_text(&buf2, k.k->p);
+				panic("expected end %s got %s\n", buf1.buf, buf2.buf);
 			}
 			break;
 		}
@@ -1151,10 +1151,11 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
 	invalid = bch2_bkey_invalid(c, bkey_i_to_s_c(insert), btree_node_type(b)) ?:
 		bch2_bkey_in_btree_node(b, bkey_i_to_s_c(insert));
 	if (invalid) {
-		char buf[160];
+		struct printbuf buf = PRINTBUF;
 
-		bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(insert));
-		bch2_fs_inconsistent(c, "inserting invalid bkey %s: %s", buf, invalid);
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
+		bch2_fs_inconsistent(c, "inserting invalid bkey %s: %s", buf.buf, invalid);
+		printbuf_exit(&buf);
 		dump_stack();
 	}
 
@@ -1636,15 +1637,17 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
 	}
 
 	if (bkey_cmp(bpos_successor(prev->data->max_key), next->data->min_key)) {
-		char buf1[100], buf2[100];
+		struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
-		bch2_bpos_to_text(&PBUF(buf1), prev->data->max_key);
-		bch2_bpos_to_text(&PBUF(buf2), next->data->min_key);
+		bch2_bpos_to_text(&buf1, prev->data->max_key);
+		bch2_bpos_to_text(&buf2, next->data->min_key);
 		bch_err(c,
 			"btree topology error in btree merge:\n"
 			"  prev ends at   %s\n"
 			"  next starts at %s",
-			buf1, buf2);
+			buf1.buf, buf2.buf);
+		printbuf_exit(&buf1);
+		printbuf_exit(&buf2);
 		bch2_topology_error(c);
 		ret = -EIO;
 		goto err;
diff --git a/fs/bcachefs/btree_update_leaf.c b/fs/bcachefs/btree_update_leaf.c
index e9e10df8ee95..4b0e00f32a96 100644
--- a/fs/bcachefs/btree_update_leaf.c
+++ b/fs/bcachefs/btree_update_leaf.c
@@ -831,11 +831,12 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans,
 		const char *invalid = bch2_bkey_invalid(c,
 				bkey_i_to_s_c(i->k), i->bkey_type);
 		if (invalid) {
-			char buf[200];
+			struct printbuf buf = PRINTBUF;
 
-			bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(i->k));
+			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(i->k));
 			bch2_fs_fatal_error(c, "invalid bkey %s on insert from %s -> %ps: %s\n",
-					    buf, trans->fn, (void *) i->ip_allocated, invalid);
+					    buf.buf, trans->fn, (void *) i->ip_allocated, invalid);
+			printbuf_exit(&buf);
 			return -EINVAL;
 		}
 		btree_insert_entry_checks(trans, i);
diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index 136a5727ea20..7d3636e20c81 100644
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -376,22 +376,23 @@ static inline int update_replicas(struct bch_fs *c, struct bkey_s_c k,
 {
 	struct bch_fs_usage __percpu *fs_usage;
 	int idx, ret = 0;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 
 	percpu_down_read(&c->mark_lock);
+	buf.atomic++;
 
 	idx = bch2_replicas_entry_idx(c, r);
 	if (idx < 0 &&
 	    (test_bit(BCH_FS_REBUILD_REPLICAS, &c->flags) ||
 	     fsck_err(c, "no replicas entry\n"
 		      "  while marking %s",
-		      (bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)))) {
+		      (bch2_bkey_val_to_text(&buf, c, k), buf.buf)))) {
 		percpu_up_read(&c->mark_lock);
 		ret = bch2_mark_replicas(c, r);
-		if (ret)
-			return ret;
-
 		percpu_down_read(&c->mark_lock);
+
+		if (ret)
+			goto err;
 		idx = bch2_replicas_entry_idx(c, r);
 	}
 	if (idx < 0) {
@@ -407,6 +408,7 @@ static inline int update_replicas(struct bch_fs *c, struct bkey_s_c k,
 err:
 fsck_err:
 	percpu_up_read(&c->mark_lock);
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -678,7 +680,8 @@ static int check_bucket_ref(struct bch_fs *c,
 	u16 bucket_sectors = !ptr->cached
 		? dirty_sectors
 		: cached_sectors;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
+	int ret = 0;
 
 	if (gen_after(ptr->gen, b_gen)) {
 		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
@@ -687,8 +690,9 @@ static int check_bucket_ref(struct bch_fs *c,
 			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			ptr->gen,
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
-		return -EIO;
+			(bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
 	}
 
 	if (gen_cmp(b_gen, ptr->gen) > BUCKET_GC_GEN_MAX) {
@@ -698,8 +702,10 @@ static int check_bucket_ref(struct bch_fs *c,
 			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			ptr->gen,
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
-		return -EIO;
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
 	}
 
 	if (b_gen != ptr->gen && !ptr->cached) {
@@ -710,12 +716,16 @@ static int check_bucket_ref(struct bch_fs *c,
 			*bucket_gen(ca, bucket_nr),
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			ptr->gen,
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
-		return -EIO;
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
 	}
 
-	if (b_gen != ptr->gen)
-		return 1;
+	if (b_gen != ptr->gen) {
+		ret = 1;
+		goto err;
+	}
 
 	if (bucket_data_type && ptr_data_type &&
 	    bucket_data_type != ptr_data_type) {
@@ -725,8 +735,10 @@ static int check_bucket_ref(struct bch_fs *c,
 			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type],
 			bch2_data_types[ptr_data_type],
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
-		return -EIO;
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
 	}
 
 	if ((unsigned) (bucket_sectors + sectors) > U16_MAX) {
@@ -736,11 +748,14 @@ static int check_bucket_ref(struct bch_fs *c,
 			ptr->dev, bucket_nr, b_gen,
 			bch2_data_types[bucket_data_type ?: ptr_data_type],
 			bucket_sectors, sectors,
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
-		return -EIO;
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		ret = -EIO;
+		goto err;
 	}
-
-	return 0;
+err:
+	printbuf_exit(&buf);
+	return ret;
 }
 
 static int mark_stripe_bucket(struct btree_trans *trans,
@@ -759,7 +774,7 @@ static int mark_stripe_bucket(struct btree_trans *trans,
 	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 	struct bucket *g;
 	struct bucket_mark new, old;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	BUG_ON(!(flags & BTREE_TRIGGER_GC));
@@ -767,6 +782,7 @@ static int mark_stripe_bucket(struct btree_trans *trans,
 	/* * XXX doesn't handle deletion */
 
 	percpu_down_read(&c->mark_lock);
+	buf.atomic++;
 	g = PTR_GC_BUCKET(ca, ptr);
 
 	if (g->mark.dirty_sectors ||
@@ -774,7 +790,7 @@ static int mark_stripe_bucket(struct btree_trans *trans,
 		bch2_fs_inconsistent(c,
 			      "bucket %u:%zu gen %u: multiple stripes using same bucket\n%s",
 			      ptr->dev, PTR_BUCKET_NR(ca, ptr), g->mark.gen,
-			      (bch2_bkey_val_to_text(&PBUF(buf), c, k), buf));
+			      (bch2_bkey_val_to_text(&buf, c, k), buf.buf));
 		ret = -EINVAL;
 		goto err;
 	}
@@ -799,8 +815,8 @@ static int mark_stripe_bucket(struct btree_trans *trans,
 	bch2_dev_usage_update(c, ca, old, new, journal_seq, true);
 err:
 	percpu_up_read(&c->mark_lock);
-
-	return 0;
+	printbuf_exit(&buf);
+	return ret;
 }
 
 static int __mark_pointer(struct btree_trans *trans,
@@ -987,10 +1003,11 @@ static int bch2_mark_extent(struct btree_trans *trans,
 	if (r.e.nr_devs) {
 		ret = update_replicas(c, k, &r.e, dirty_sectors, journal_seq, true);
 		if (ret) {
-			char buf[200];
+			struct printbuf buf = PRINTBUF;
 
-			bch2_bkey_val_to_text(&PBUF(buf), c, k);
-			bch2_fs_fatal_error(c, "no replicas entry for %s", buf);
+			bch2_bkey_val_to_text(&buf, c, k);
+			bch2_fs_fatal_error(c, "no replicas entry for %s", buf.buf);
+			printbuf_exit(&buf);
 			return ret;
 		}
 	}
@@ -1019,13 +1036,16 @@ static int bch2_mark_stripe(struct btree_trans *trans,
 		struct stripe *m = genradix_ptr(&c->stripes, idx);
 
 		if (!m || (old_s && !m->alive)) {
-			char buf1[200], buf2[200];
+			struct printbuf buf1 = PRINTBUF;
+			struct printbuf buf2 = PRINTBUF;
 
-			bch2_bkey_val_to_text(&PBUF(buf1), c, old);
-			bch2_bkey_val_to_text(&PBUF(buf2), c, new);
+			bch2_bkey_val_to_text(&buf1, c, old);
+			bch2_bkey_val_to_text(&buf2, c, new);
 			bch_err_ratelimited(c, "error marking nonexistent stripe %llu while marking\n"
 					    "old %s\n"
-					    "new %s", idx, buf1, buf2);
+					    "new %s", idx, buf1.buf, buf2.buf);
+			printbuf_exit(&buf2);
+			printbuf_exit(&buf1);
 			bch2_inconsistent_error(c);
 			return -1;
 		}
@@ -1090,10 +1110,11 @@ static int bch2_mark_stripe(struct btree_trans *trans,
 				      ((s64) m->sectors * m->nr_redundant),
 				      journal_seq, gc);
 		if (ret) {
-			char buf[200];
+			struct printbuf buf = PRINTBUF;
 
-			bch2_bkey_val_to_text(&PBUF(buf), c, new);
-			bch2_fs_fatal_error(c, "no replicas entry for %s", buf);
+			bch2_bkey_val_to_text(&buf, c, new);
+			bch2_fs_fatal_error(c, "no replicas entry for %s", buf.buf);
+			printbuf_exit(&buf);
 			return ret;
 		}
 	}
@@ -1174,7 +1195,7 @@ static s64 __bch2_mark_reflink_p(struct btree_trans *trans,
 	int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
 	u64 next_idx = end;
 	s64 ret = 0;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 
 	if (r_idx >= c->reflink_gc_nr)
 		goto not_found;
@@ -1193,7 +1214,7 @@ not_found:
 	if (fsck_err(c, "pointer to missing indirect extent\n"
 		     "  %s\n"
 		     "  missing range %llu-%llu",
-		     (bch2_bkey_val_to_text(&PBUF(buf), c, p.s_c), buf),
+		     (bch2_bkey_val_to_text(&buf, c, p.s_c), buf.buf),
 		     *idx, next_idx)) {
 		struct bkey_i_error new;
 
@@ -1207,6 +1228,7 @@ not_found:
 
 	*idx = next_idx;
 fsck_err:
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -1289,7 +1311,7 @@ void fs_usage_apply_warn(struct btree_trans *trans,
 {
 	struct bch_fs *c = trans->c;
 	struct btree_insert_entry *i;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 
 	bch_err(c, "disk usage increased %lli more than %u sectors reserved",
 		should_not_have_added, disk_res_sectors);
@@ -1298,13 +1320,17 @@ void fs_usage_apply_warn(struct btree_trans *trans,
 		struct bkey_s_c old = { &i->old_k, i->old_v };
 
 		pr_err("while inserting");
-		bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(i->k));
-		pr_err("  %s", buf);
+		printbuf_reset(&buf);
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(i->k));
+		pr_err("  %s", buf.buf);
 		pr_err("overlapping with");
-		bch2_bkey_val_to_text(&PBUF(buf), c, old);
-		pr_err("  %s", buf);
+		printbuf_reset(&buf);
+		bch2_bkey_val_to_text(&buf, c, old);
+		pr_err("  %s", buf.buf);
 	}
+
 	__WARN();
+	printbuf_exit(&buf);
 }
 
 int bch2_trans_fs_usage_apply(struct btree_trans *trans,
@@ -1744,7 +1770,7 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
 	struct bkey_i *n;
 	__le64 *refcount;
 	int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret;
 
 	bch2_trans_iter_init(trans, &iter, BTREE_ID_reflink, POS(0, *idx),
@@ -1764,19 +1790,19 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
 
 	refcount = bkey_refcount(n);
 	if (!refcount) {
-		bch2_bkey_val_to_text(&PBUF(buf), c, p.s_c);
+		bch2_bkey_val_to_text(&buf, c, p.s_c);
 		bch2_fs_inconsistent(c,
 			"nonexistent indirect extent at %llu while marking\n  %s",
-			*idx, buf);
+			*idx, buf.buf);
 		ret = -EIO;
 		goto err;
 	}
 
 	if (!*refcount && (flags & BTREE_TRIGGER_OVERWRITE)) {
-		bch2_bkey_val_to_text(&PBUF(buf), c, p.s_c);
+		bch2_bkey_val_to_text(&buf, c, p.s_c);
 		bch2_fs_inconsistent(c,
 			"indirect extent refcount underflow at %llu while marking\n  %s",
-			*idx, buf);
+			*idx, buf.buf);
 		ret = -EIO;
 		goto err;
 	}
@@ -1811,6 +1837,7 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
 	*idx = k.k->p.offset;
 err:
 	bch2_trans_iter_exit(trans, &iter);
+	printbuf_exit(&buf);
 	return ret;
 }
 
diff --git a/fs/bcachefs/clock.c b/fs/bcachefs/clock.c
index da91c95e3ffc..342797303415 100644
--- a/fs/bcachefs/clock.c
+++ b/fs/bcachefs/clock.c
@@ -157,6 +157,7 @@ void bch2_io_timers_to_text(struct printbuf *out, struct io_clock *clock)
 	unsigned long now;
 	unsigned i;
 
+	out->atomic++;
 	spin_lock(&clock->timer_lock);
 	now = atomic64_read(&clock->now);
 
@@ -165,6 +166,7 @@ void bch2_io_timers_to_text(struct printbuf *out, struct io_clock *clock)
 		       clock->timers.data[i]->fn,
 		       clock->timers.data[i]->expire - now);
 	spin_unlock(&clock->timer_lock);
+	--out->atomic;
 }
 
 void bch2_io_clock_exit(struct io_clock *clock)
diff --git a/fs/bcachefs/debug.c b/fs/bcachefs/debug.c
index 02a5ef5ecb3e..c3bfa7f1d77d 100644
--- a/fs/bcachefs/debug.c
+++ b/fs/bcachefs/debug.c
@@ -169,10 +169,11 @@ void __bch2_btree_verify(struct bch_fs *c, struct btree *b)
 		failed |= bch2_btree_verify_replica(c, b, p);
 
 	if (failed) {
-		char buf[200];
+		struct printbuf buf = PRINTBUF;
 
-		bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(&b->key));
-		bch2_fs_fatal_error(c, "btree node verify failed for : %s\n", buf);
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
+		bch2_fs_fatal_error(c, "btree node verify failed for : %s\n", buf.buf);
+		printbuf_exit(&buf);
 	}
 out:
 	mutex_unlock(&c->verify_lock);
@@ -188,8 +189,7 @@ struct dump_iter {
 	struct bch_fs	*c;
 	enum btree_id		id;
 
-	char			buf[1 << 12];
-	size_t			bytes;	/* what's currently in buf */
+	struct printbuf		buf;
 
 	char __user		*ubuf;	/* destination user buffer */
 	size_t			size;	/* size of requested read */
@@ -198,9 +198,9 @@ struct dump_iter {
 
 static int flush_buf(struct dump_iter *i)
 {
-	if (i->bytes) {
-		size_t bytes = min(i->bytes, i->size);
-		int err = copy_to_user(i->ubuf, i->buf, bytes);
+	if (i->buf.pos) {
+		size_t bytes = min_t(size_t, i->buf.pos, i->size);
+		int err = copy_to_user(i->ubuf, i->buf.buf, bytes);
 
 		if (err)
 			return err;
@@ -208,8 +208,8 @@ static int flush_buf(struct dump_iter *i)
 		i->ret	 += bytes;
 		i->ubuf	 += bytes;
 		i->size	 -= bytes;
-		i->bytes -= bytes;
-		memmove(i->buf, i->buf + bytes, i->bytes);
+		i->buf.pos -= bytes;
+		memmove(i->buf.buf, i->buf.buf + bytes, i->buf.pos);
 	}
 
 	return 0;
@@ -228,13 +228,17 @@ static int bch2_dump_open(struct inode *inode, struct file *file)
 	i->from = POS_MIN;
 	i->c	= container_of(bd, struct bch_fs, btree_debug[bd->id]);
 	i->id	= bd->id;
+	i->buf	= PRINTBUF;
 
 	return 0;
 }
 
 static int bch2_dump_release(struct inode *inode, struct file *file)
 {
-	kfree(file->private_data);
+	struct dump_iter *i = file->private_data;
+
+	printbuf_exit(&i->buf);
+	kfree(i);
 	return 0;
 }
 
@@ -266,11 +270,8 @@ static ssize_t bch2_read_btree(struct file *file, char __user *buf,
 	k = bch2_btree_iter_peek(&iter);
 
 	while (k.k && !(err = bkey_err(k))) {
-		bch2_bkey_val_to_text(&PBUF(i->buf), i->c, k);
-		i->bytes = strlen(i->buf);
-		BUG_ON(i->bytes >= sizeof(i->buf));
-		i->buf[i->bytes] = '\n';
-		i->bytes++;
+		bch2_bkey_val_to_text(&i->buf, i->c, k);
+		pr_char(&i->buf, '\n');
 
 		k = bch2_btree_iter_next(&iter);
 		i->from = iter.pos;
@@ -319,8 +320,7 @@ static ssize_t bch2_read_btree_formats(struct file *file, char __user *buf,
 	bch2_trans_init(&trans, i->c, 0, 0);
 
 	for_each_btree_node(&trans, iter, i->id, i->from, 0, b, err) {
-		bch2_btree_node_to_text(&PBUF(i->buf), i->c, b);
-		i->bytes = strlen(i->buf);
+		bch2_btree_node_to_text(&i->buf, i->c, b);
 		err = flush_buf(i);
 		if (err)
 			break;
@@ -384,16 +384,14 @@ static ssize_t bch2_read_bfloat_failed(struct file *file, char __user *buf,
 			bch2_btree_node_iter_peek(&l->iter, l->b);
 
 		if (l->b != prev_node) {
-			bch2_btree_node_to_text(&PBUF(i->buf), i->c, l->b);
-			i->bytes = strlen(i->buf);
+			bch2_btree_node_to_text(&i->buf, i->c, l->b);
 			err = flush_buf(i);
 			if (err)
 				break;
 		}
 		prev_node = l->b;
 
-		bch2_bfloat_to_text(&PBUF(i->buf), l->b, _k);
-		i->bytes = strlen(i->buf);
+		bch2_bfloat_to_text(&i->buf, l->b, _k);
 		err = flush_buf(i);
 		if (err)
 			break;
diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 86421f65d139..b220b523d856 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -286,14 +286,15 @@ static void ec_validate_checksums(struct bch_fs *c, struct ec_stripe_buf *buf)
 			struct bch_csum got = ec_block_checksum(buf, i, offset);
 
 			if (bch2_crc_cmp(want, got)) {
-				char buf2[200];
+				struct printbuf buf2 = PRINTBUF;
 
-				bch2_bkey_val_to_text(&PBUF(buf2), c, bkey_i_to_s_c(&buf->key.k_i));
+				bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(&buf->key.k_i));
 
 				bch_err_ratelimited(c,
 					"stripe checksum error for %ps at %u:%u: csum type %u, expected %llx got %llx\n%s",
 					(void *) _RET_IP_, i, j, v->csum_type,
-					want.lo, got.lo, buf2);
+					want.lo, got.lo, buf2.buf);
+				printbuf_exit(&buf2);
 				clear_bit(i, buf->valid);
 				break;
 			}
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 9e8b085e36d7..2aaeee585157 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -1676,7 +1676,8 @@ static int bch2_show_options(struct seq_file *seq, struct dentry *root)
 {
 	struct bch_fs *c = root->d_sb->s_fs_info;
 	enum bch_opt_id i;
-	char buf[512];
+	struct printbuf buf = PRINTBUF;
+	int ret = 0;
 
 	for (i = 0; i < bch2_opts_nr; i++) {
 		const struct bch_option *opt = &bch2_opt_table[i];
@@ -1688,13 +1689,17 @@ static int bch2_show_options(struct seq_file *seq, struct dentry *root)
 		if (v == bch2_opt_get_by_id(&bch2_opts_default, i))
 			continue;
 
-		bch2_opt_to_text(&PBUF(buf), c, opt, v,
+		printbuf_reset(&buf);
+		bch2_opt_to_text(&buf, c, opt, v,
 				 OPT_SHOW_MOUNT_STYLE);
 		seq_putc(seq, ',');
-		seq_puts(seq, buf);
+		seq_puts(seq, buf.buf);
 	}
 
-	return 0;
+	if (buf.allocation_failure)
+		ret = -ENOMEM;
+	printbuf_exit(&buf);
+	return ret;
 }
 
 static void bch2_put_super(struct super_block *sb)
diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index ced4d671eb8d..8783b950055e 100644
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -698,15 +698,16 @@ static int check_key_has_snapshot(struct btree_trans *trans,
 				  struct bkey_s_c k)
 {
 	struct bch_fs *c = trans->c;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	if (mustfix_fsck_err_on(!snapshot_t(c, k.k->p.snapshot)->equiv, c,
 			"key in missing snapshot: %s",
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)))
-		return bch2_btree_delete_at(trans, iter,
+			(bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
+		ret = bch2_btree_delete_at(trans, iter,
 					    BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?: 1;
 fsck_err:
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -746,7 +747,7 @@ static int hash_check_key(struct btree_trans *trans,
 {
 	struct bch_fs *c = trans->c;
 	struct btree_iter iter = { NULL };
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	struct bkey_s_c k;
 	u64 hash;
 	int ret = 0;
@@ -770,8 +771,9 @@ static int hash_check_key(struct btree_trans *trans,
 		if (fsck_err_on(k.k->type == desc.key_type &&
 				!desc.cmp_bkey(k, hash_k), c,
 				"duplicate hash table keys:\n%s",
-				(bch2_bkey_val_to_text(&PBUF(buf), c,
-						       hash_k), buf))) {
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, hash_k),
+				 buf.buf))) {
 			ret = bch2_hash_delete_at(trans, desc, hash_info, k_iter, 0) ?: 1;
 			break;
 		}
@@ -782,13 +784,16 @@ static int hash_check_key(struct btree_trans *trans,
 		}
 
 	}
+out:
 	bch2_trans_iter_exit(trans, &iter);
+	printbuf_exit(&buf);
 	return ret;
 bad_hash:
 	if (fsck_err(c, "hash table key at wrong offset: btree %u inode %llu offset %llu, "
 		     "hashed to %llu\n%s",
 		     desc.btree_id, hash_k.k->p.inode, hash_k.k->p.offset, hash,
-		     (bch2_bkey_val_to_text(&PBUF(buf), c, hash_k), buf)) == FSCK_ERR_IGNORE)
+		     (printbuf_reset(&buf),
+		      bch2_bkey_val_to_text(&buf, c, hash_k), buf.buf)) == FSCK_ERR_IGNORE)
 		return 0;
 
 	ret = hash_redo_key(trans, desc, hash_info, k_iter, hash_k);
@@ -796,9 +801,9 @@ bad_hash:
 		bch_err(c, "hash_redo_key err %i", ret);
 		return ret;
 	}
-	return -EINTR;
+	ret = -EINTR;
 fsck_err:
-	return ret;
+	goto out;
 }
 
 static int check_inode(struct btree_trans *trans,
@@ -1166,32 +1171,34 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
 	struct bch_fs *c = trans->c;
 	struct bkey_s_c k;
 	struct inode_walker_entry *i;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	k = bch2_btree_iter_peek(iter);
 	if (!k.k)
-		return 0;
+		goto out;
 
 	ret = bkey_err(k);
 	if (ret)
-		return ret;
+		goto err;
 
 	ret = check_key_has_snapshot(trans, iter, k);
-	if (ret)
-		return ret < 0 ? ret : 0;
+	if (ret) {
+		ret = ret < 0 ? ret : 0;
+		goto out;
+	}
 
 	ret = snapshots_seen_update(c, s, k.k->p);
 	if (ret)
-		return ret;
+		goto err;
 
 	if (k.k->type == KEY_TYPE_whiteout)
-		return 0;
+		goto out;
 
 	if (inode->cur_inum != k.k->p.inode) {
 		ret = check_i_sectors(trans, inode);
 		if (ret)
-			return ret;
+			goto err;
 	}
 #if 0
 	if (bkey_cmp(prev.k->k.p, bkey_start_pos(k.k)) > 0) {
@@ -1201,22 +1208,29 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
 		bch2_bkey_val_to_text(&PBUF(buf1), c, bkey_i_to_s_c(prev.k));
 		bch2_bkey_val_to_text(&PBUF(buf2), c, k);
 
-		if (fsck_err(c, "overlapping extents:\n%s\n%s", buf1, buf2))
-			return fix_overlapping_extent(trans, k, prev.k->k.p) ?: -EINTR;
+		if (fsck_err(c, "overlapping extents:\n%s\n%s", buf1, buf2)) {
+			ret = fix_overlapping_extent(trans, k, prev.k->k.p) ?: -EINTR;
+			goto out;
+		}
 	}
 #endif
 	ret = __walk_inode(trans, inode, k.k->p);
 	if (ret < 0)
-		return ret;
+		goto err;
 
 	if (fsck_err_on(ret == INT_MAX, c,
 			"extent in missing inode:\n  %s",
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)))
-		return bch2_btree_delete_at(trans, iter,
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
+		ret = bch2_btree_delete_at(trans, iter,
 					    BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+		goto out;
+	}
 
-	if (ret == INT_MAX)
-		return 0;
+	if (ret == INT_MAX) {
+		ret = 0;
+		goto out;
+	}
 
 	i = inode->d + ret;
 	ret = 0;
@@ -1225,9 +1239,12 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
 			!S_ISLNK(i->inode.bi_mode), c,
 			"extent in non regular inode mode %o:\n  %s",
 			i->inode.bi_mode,
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)))
-		return bch2_btree_delete_at(trans, iter,
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
+		ret = bch2_btree_delete_at(trans, iter,
 					    BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+		goto out;
+	}
 
 	if (!bch2_snapshot_internal_node(c, k.k->p.snapshot)) {
 		for_each_visible_inode(c, s, inode, k.k->p.snapshot, i) {
@@ -1237,11 +1254,12 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
 					"extent type %u offset %llu past end of inode %llu, i_size %llu",
 					k.k->type, k.k->p.offset, k.k->p.inode, i->inode.bi_size)) {
 				bch2_fs_lazy_rw(c);
-				return bch2_btree_delete_range_trans(trans, BTREE_ID_extents,
+				ret = bch2_btree_delete_range_trans(trans, BTREE_ID_extents,
 						SPOS(k.k->p.inode, round_up(i->inode.bi_size, block_bytes(c)) >> 9,
 						     k.k->p.snapshot),
 						POS(k.k->p.inode, U64_MAX),
 						0, NULL) ?: -EINTR;
+				goto out;
 			}
 		}
 	}
@@ -1253,7 +1271,10 @@ static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
 	bch2_bkey_buf_reassemble(&prev, c, k);
 #endif
 
+out:
+err:
 fsck_err:
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -1351,7 +1372,7 @@ static int check_dirent_target(struct btree_trans *trans,
 	struct bch_fs *c = trans->c;
 	struct bkey_i_dirent *n;
 	bool backpointer_exists = true;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret = 0;
 
 	if (!target->bi_dir &&
@@ -1377,9 +1398,7 @@ static int check_dirent_target(struct btree_trans *trans,
 				"directory %llu with multiple links",
 				target->bi_inum)) {
 			ret = __remove_dirent(trans, d.k->p);
-			if (ret)
-				goto err;
-			return 0;
+			goto out;
 		}
 
 		if (fsck_err_on(backpointer_exists &&
@@ -1416,18 +1435,19 @@ static int check_dirent_target(struct btree_trans *trans,
 			"incorrect d_type: got %s, should be %s:\n%s",
 			bch2_d_type_str(d.v->d_type),
 			bch2_d_type_str(inode_d_type(target)),
-			(bch2_bkey_val_to_text(&PBUF(buf), c, d.s_c), buf))) {
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf))) {
 		n = bch2_trans_kmalloc(trans, bkey_bytes(d.k));
 		ret = PTR_ERR_OR_ZERO(n);
 		if (ret)
-			return ret;
+			goto err;
 
 		bkey_reassemble(&n->k_i, d.s_c);
 		n->v.d_type = inode_d_type(target);
 
 		ret = bch2_trans_update(trans, iter, &n->k_i, 0);
 		if (ret)
-			return ret;
+			goto err;
 
 		d = dirent_i_to_s_c(n);
 	}
@@ -1441,19 +1461,21 @@ static int check_dirent_target(struct btree_trans *trans,
 		n = bch2_trans_kmalloc(trans, bkey_bytes(d.k));
 		ret = PTR_ERR_OR_ZERO(n);
 		if (ret)
-			return ret;
+			goto err;
 
 		bkey_reassemble(&n->k_i, d.s_c);
 		n->v.d_parent_subvol = cpu_to_le32(target->bi_parent_subvol);
 
 		ret = bch2_trans_update(trans, iter, &n->k_i, 0);
 		if (ret)
-			return ret;
+			goto err;
 
 		d = dirent_i_to_s_c(n);
 	}
+out:
 err:
 fsck_err:
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -1467,46 +1489,53 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 	struct bkey_s_c k;
 	struct bkey_s_c_dirent d;
 	struct inode_walker_entry *i;
-	char buf[200];
-	int ret;
+	struct printbuf buf = PRINTBUF;
+	int ret = 0;
 
 	k = bch2_btree_iter_peek(iter);
 	if (!k.k)
-		return 0;
+		goto out;
 
 	ret = bkey_err(k);
 	if (ret)
-		return ret;
+		goto err;
 
 	ret = check_key_has_snapshot(trans, iter, k);
-	if (ret)
-		return ret < 0 ? ret : 0;
+	if (ret) {
+		ret = ret < 0 ? ret : 0;
+		goto out;
+	}
 
 	ret = snapshots_seen_update(c, s, k.k->p);
 	if (ret)
-		return ret;
+		goto err;
 
 	if (k.k->type == KEY_TYPE_whiteout)
-		return 0;
+		goto out;
 
 	if (dir->cur_inum != k.k->p.inode) {
 		ret = check_subdir_count(trans, dir);
 		if (ret)
-			return ret;
+			goto err;
 	}
 
 	ret = __walk_inode(trans, dir, k.k->p);
 	if (ret < 0)
-		return ret;
+		goto err;
 
 	if (fsck_err_on(ret == INT_MAX, c,
 			"dirent in nonexisting directory:\n%s",
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)))
-		return bch2_btree_delete_at(trans, iter,
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
+		ret = bch2_btree_delete_at(trans, iter,
 				BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+		goto out;
+	}
 
-	if (ret == INT_MAX)
-		return 0;
+	if (ret == INT_MAX) {
+		ret = 0;
+		goto out;
+	}
 
 	i = dir->d + ret;
 	ret = 0;
@@ -1514,8 +1543,11 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 	if (fsck_err_on(!S_ISDIR(i->inode.bi_mode), c,
 			"dirent in non directory inode type %s:\n%s",
 			bch2_d_type_str(inode_d_type(&i->inode)),
-			(bch2_bkey_val_to_text(&PBUF(buf), c, k), buf)))
-		return bch2_btree_delete_at(trans, iter, 0);
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
+		ret = bch2_btree_delete_at(trans, iter, 0);
+		goto out;
+	}
 
 	if (dir->first_this_inode)
 		*hash_info = bch2_hash_info_init(c, &dir->d[0].inode);
@@ -1523,12 +1555,15 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 	ret = hash_check_key(trans, bch2_dirent_hash_desc,
 			     hash_info, iter, k);
 	if (ret < 0)
-		return ret;
-	if (ret) /* dirent has been deleted */
-		return 0;
+		goto err;
+	if (ret) {
+		/* dirent has been deleted */
+		ret = 0;
+		goto out;
+	}
 
 	if (k.k->type != KEY_TYPE_dirent)
-		return 0;
+		goto out;
 
 	d = bkey_s_c_to_dirent(k);
 
@@ -1541,24 +1576,27 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 		ret = __subvol_lookup(trans, target_subvol,
 				      &target_snapshot, &target_inum);
 		if (ret && ret != -ENOENT)
-			return ret;
+			goto err;
 
 		if (fsck_err_on(ret, c,
 				"dirent points to missing subvolume %llu",
-				le64_to_cpu(d.v->d_child_subvol)))
-			return __remove_dirent(trans, d.k->p);
+				le64_to_cpu(d.v->d_child_subvol))) {
+			ret = __remove_dirent(trans, d.k->p);
+			goto err;
+		}
 
 		ret = __lookup_inode(trans, target_inum,
 				   &subvol_root, &target_snapshot);
 		if (ret && ret != -ENOENT)
-			return ret;
+			goto err;
 
 		if (fsck_err_on(ret, c,
 				"subvolume %u points to missing subvolume root %llu",
 				target_subvol,
 				target_inum)) {
 			bch_err(c, "repair not implemented yet");
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err;
 		}
 
 		if (fsck_err_on(subvol_root.bi_subvol != target_subvol, c,
@@ -1568,32 +1606,33 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 			subvol_root.bi_subvol = target_subvol;
 			ret = __write_inode(trans, &subvol_root, target_snapshot);
 			if (ret)
-				return ret;
+				goto err;
 		}
 
 		ret = check_dirent_target(trans, iter, d, &subvol_root,
 					  target_snapshot);
 		if (ret)
-			return ret;
+			goto err;
 	} else {
 		ret = __get_visible_inodes(trans, target, s, le64_to_cpu(d.v->d_inum));
 		if (ret)
-			return ret;
+			goto err;
 
 		if (fsck_err_on(!target->nr, c,
 				"dirent points to missing inode:\n%s",
-				(bch2_bkey_val_to_text(&PBUF(buf), c,
-						       k), buf))) {
+				(printbuf_reset(&buf),
+				 bch2_bkey_val_to_text(&buf, c, k),
+				 buf.buf))) {
 			ret = __remove_dirent(trans, d.k->p);
 			if (ret)
-				return ret;
+				goto err;
 		}
 
 		for (i = target->d; i < target->d + target->nr; i++) {
 			ret = check_dirent_target(trans, iter, d,
 						  &i->inode, i->snapshot);
 			if (ret)
-				return ret;
+				goto err;
 		}
 	}
 
@@ -1601,7 +1640,10 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 		for_each_visible_inode(c, s, dir, d.k->p.snapshot, i)
 			i->count++;
 
+out:
+err:
 fsck_err:
+	printbuf_exit(&buf);
 	return ret;
 }
 
diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index 4b9ff76dd19f..c9204cab055d 100644
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -2057,11 +2057,11 @@ static noinline void read_from_stale_dirty_pointer(struct btree_trans *trans,
 	struct bch_fs *c = trans->c;
 	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr.dev);
 	struct btree_iter iter;
-	char buf[200];
+	struct printbuf buf = PRINTBUF;
 	int ret;
 
-	bch2_bkey_val_to_text(&PBUF(buf), c, k);
-	bch2_fs_inconsistent(c, "Attempting to read from stale dirty pointer: %s", buf);
+	bch2_bkey_val_to_text(&buf, c, k);
+	bch2_fs_inconsistent(c, "Attempting to read from stale dirty pointer: %s", buf.buf);
 
 	bch2_trans_iter_init(trans, &iter, BTREE_ID_alloc,
 			     POS(ptr.dev, PTR_BUCKET_NR(ca, &ptr)),
@@ -2069,12 +2069,14 @@ static noinline void read_from_stale_dirty_pointer(struct btree_trans *trans,
 
 	ret = lockrestart_do(trans, bkey_err(k = bch2_btree_iter_peek_slot(&iter)));
 	if (ret)
-		return;
+		goto out;
 
-	bch2_bkey_val_to_text(&PBUF(buf), c, k);
-	bch_err(c, "%s", buf);
+	bch2_bkey_val_to_text(&buf, c, k);
+	bch_err(c, "%s", buf.buf);
 	bch_err(c, "memory gen: %u", *bucket_gen(ca, iter.pos.offset));
 	bch2_trans_iter_exit(trans, &iter);
+out:
+	printbuf_exit(&buf);
 }
 
 int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index 279e960f2307..a579e6483d1e 100644
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -414,18 +414,18 @@ unlock:
 	    !can_discard &&
 	    j->reservations.idx == j->reservations.unwritten_idx &&
 	    (flags & JOURNAL_RES_GET_RESERVED)) {
-		char *journal_debug_buf = kmalloc(4096, GFP_ATOMIC);
+		struct printbuf buf = PRINTBUF;
 
 		bch_err(c, "Journal stuck! Hava a pre-reservation but journal full");
-		if (journal_debug_buf) {
-			bch2_journal_debug_to_text(&_PBUF(journal_debug_buf, 4096), j);
-			bch_err(c, "%s", journal_debug_buf);
 
-			bch2_journal_pins_to_text(&_PBUF(journal_debug_buf, 4096), j);
-			bch_err(c, "Journal pins:\n%s", journal_debug_buf);
-			kfree(journal_debug_buf);
-		}
+		bch2_journal_debug_to_text(&buf, j);
+		bch_err(c, "%s", buf.buf);
+
+		printbuf_reset(&buf);
+		bch2_journal_pins_to_text(&buf, j);
+		bch_err(c, "Journal pins:\n%s", buf.buf);
 
+		printbuf_exit(&buf);
 		bch2_fatal_error(c);
 		dump_stack();
 	}
@@ -1186,6 +1186,8 @@ void __bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
 	unsigned long now = jiffies;
 	unsigned i;
 
+	out->atomic++;
+
 	rcu_read_lock();
 	s = READ_ONCE(j->reservations);
 
@@ -1270,6 +1272,8 @@ void __bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
 	}
 
 	rcu_read_unlock();
+
+	--out->atomic;
 }
 
 void bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
@@ -1286,6 +1290,8 @@ void bch2_journal_pins_to_text(struct printbuf *out, struct journal *j)
 	u64 i;
 
 	spin_lock(&j->lock);
+	out->atomic++;
+
 	fifo_for_each_entry_ptr(pin_list, &j->pin, i) {
 		pr_buf(out, "%llu: count %u\n",
 		       i, atomic_read(&pin_list->count));
@@ -1305,5 +1311,7 @@ void bch2_journal_pins_to_text(struct printbuf *out, struct journal *j)
 			pr_buf(out, "\t%px %ps\n",
 			       pin, pin->flush);
 	}
+
+	--out->atomic;
 	spin_unlock(&j->lock);
 }
diff --git a/fs/bcachefs/journal_io.c b/fs/bcachefs/journal_io.c
index 302af332b632..bbec4d85b6bc 100644
--- a/fs/bcachefs/journal_io.c
+++ b/fs/bcachefs/journal_io.c
@@ -251,14 +251,15 @@ static int journal_validate_key(struct bch_fs *c, const char *where,
 	invalid = bch2_bkey_invalid(c, bkey_i_to_s_c(k),
 				    __btree_node_type(level, btree_id));
 	if (invalid) {
-		char buf[160];
+		struct printbuf buf = PRINTBUF;
 
-		bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(k));
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(k));
 		mustfix_fsck_err(c, "invalid %s in %s entry offset %zi/%u: %s\n%s",
 				 type, where,
 				 (u64 *) k - entry->_data,
 				 le16_to_cpu(entry->u64s),
-				 invalid, buf);
+				 invalid, buf.buf);
+		printbuf_exit(&buf);
 
 		le16_add_cpu(&entry->u64s, -((u16) k->k.u64s));
 		memmove(k, bkey_next(k), next - (void *) bkey_next(k));
@@ -995,6 +996,7 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 	struct journal_replay *i, *t;
 	struct bch_dev *ca;
 	unsigned iter;
+	struct printbuf buf = PRINTBUF;
 	size_t keys = 0, entries = 0;
 	bool degraded = false;
 	u64 seq, last_seq = 0;
@@ -1053,7 +1055,8 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 
 	if (!last_seq) {
 		fsck_err(c, "journal read done, but no entries found after dropping non-flushes");
-		return -1;
+		ret = -1;
+		goto err;
 	}
 
 	/* Drop blacklisted entries and entries older than last_seq: */
@@ -1085,7 +1088,7 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 
 		while (seq < le64_to_cpu(i->j.seq)) {
 			u64 missing_start, missing_end;
-			char buf1[200], buf2[200];
+			struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
 			while (seq < le64_to_cpu(i->j.seq) &&
 			       bch2_journal_seq_is_blacklisted(c, seq, false))
@@ -1101,14 +1104,13 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 				seq++;
 
 			if (i->list.prev != list) {
-				struct printbuf out = PBUF(buf1);
 				struct journal_replay *p = list_prev_entry(i, list);
 
-				bch2_journal_ptrs_to_text(&out, c, p);
-				pr_buf(&out, " size %zu", vstruct_sectors(&p->j, c->block_bits));
+				bch2_journal_ptrs_to_text(&buf1, c, p);
+				pr_buf(&buf1, " size %zu", vstruct_sectors(&p->j, c->block_bits));
 			} else
-				sprintf(buf1, "(none)");
-			bch2_journal_ptrs_to_text(&PBUF(buf2), c, i);
+				pr_buf(&buf1, "(none)");
+			bch2_journal_ptrs_to_text(&buf2, c, i);
 
 			missing_end = seq - 1;
 			fsck_err(c, "journal entries %llu-%llu missing! (replaying %llu-%llu)\n"
@@ -1116,7 +1118,10 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 				 "  next at %s",
 				 missing_start, missing_end,
 				 last_seq, *blacklist_seq - 1,
-				 buf1, buf2);
+				 buf1.buf, buf2.buf);
+
+			printbuf_exit(&buf1);
+			printbuf_exit(&buf2);
 		}
 
 		seq++;
@@ -1130,14 +1135,13 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 			.e.nr_required = 1,
 		};
 		unsigned ptr;
-		char buf[80];
 
 		if (i->ignore)
 			continue;
 
 		ret = jset_validate_entries(c, &i->j, READ);
 		if (ret)
-			goto fsck_err;
+			goto err;
 
 		for (ptr = 0; ptr < i->nr_ptrs; ptr++)
 			replicas.e.devs[replicas.e.nr_devs++] = i->ptrs[ptr].dev;
@@ -1149,15 +1153,17 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 		 * the devices - this is wrong:
 		 */
 
+		printbuf_reset(&buf);
+		bch2_replicas_entry_to_text(&buf, &replicas.e);
+
 		if (!degraded &&
 		    (test_bit(BCH_FS_REBUILD_REPLICAS, &c->flags) ||
 		     fsck_err_on(!bch2_replicas_marked(c, &replicas.e), c,
 				 "superblock not marked as containing replicas %s",
-				 (bch2_replicas_entry_to_text(&PBUF(buf),
-							      &replicas.e), buf)))) {
+				 buf.buf))) {
 			ret = bch2_mark_replicas(c, &replicas.e);
 			if (ret)
-				return ret;
+				goto err;
 		}
 
 		for_each_jset_key(k, _n, entry, &i->j)
@@ -1171,7 +1177,9 @@ int bch2_journal_read(struct bch_fs *c, struct list_head *list,
 	if (*start_seq != *blacklist_seq)
 		bch_info(c, "dropped unflushed entries %llu-%llu",
 			 *blacklist_seq, *start_seq - 1);
+err:
 fsck_err:
+	printbuf_exit(&buf);
 	return ret;
 }
 
@@ -1481,7 +1489,7 @@ void bch2_journal_write(struct closure *cl)
 	struct jset_entry *start, *end;
 	struct jset *jset;
 	struct bio *bio;
-	char *journal_debug_buf = NULL;
+	struct printbuf journal_debug_buf = PRINTBUF;
 	bool validate_before_checksum = false;
 	unsigned i, sectors, bytes, u64s, nr_rw_members = 0;
 	int ret;
@@ -1586,11 +1594,8 @@ retry_alloc:
 		goto retry_alloc;
 	}
 
-	if (ret) {
-		journal_debug_buf = kmalloc(4096, GFP_ATOMIC);
-		if (journal_debug_buf)
-			__bch2_journal_debug_to_text(&_PBUF(journal_debug_buf, 4096), j);
-	}
+	if (ret)
+		__bch2_journal_debug_to_text(&journal_debug_buf, j);
 
 	/*
 	 * write is allocated, no longer need to account for it in
@@ -1607,8 +1612,8 @@ retry_alloc:
 
 	if (ret) {
 		bch_err(c, "Unable to allocate journal write:\n%s",
-			journal_debug_buf);
-		kfree(journal_debug_buf);
+			journal_debug_buf.buf);
+		printbuf_exit(&journal_debug_buf);
 		bch2_fatal_error(c);
 		continue_at(cl, journal_write_done, c->io_complete_wq);
 		return;
diff --git a/fs/bcachefs/journal_reclaim.c b/fs/bcachefs/journal_reclaim.c
index c15b18831512..2d5382a83003 100644
--- a/fs/bcachefs/journal_reclaim.c
+++ b/fs/bcachefs/journal_reclaim.c
@@ -216,14 +216,11 @@ void bch2_journal_space_available(struct journal *j)
 	if (!clean_ondisk &&
 	    j->reservations.idx ==
 	    j->reservations.unwritten_idx) {
-		char *buf = kmalloc(4096, GFP_ATOMIC);
+		struct printbuf buf = PRINTBUF;
 
-		bch_err(c, "journal stuck");
-		if (buf) {
-			__bch2_journal_debug_to_text(&_PBUF(buf, 4096), j);
-			pr_err("\n%s", buf);
-			kfree(buf);
-		}
+		__bch2_journal_debug_to_text(&buf, j);
+		bch_err(c, "journal stuck\n%s", buf.buf);
+		printbuf_exit(&buf);
 
 		bch2_fatal_error(c);
 		ret = cur_entry_journal_stuck;
diff --git a/fs/bcachefs/rebalance.c b/fs/bcachefs/rebalance.c
index fe0a1dbac199..babf98894e87 100644
--- a/fs/bcachefs/rebalance.c
+++ b/fs/bcachefs/rebalance.c
@@ -257,35 +257,47 @@ void bch2_rebalance_work_to_text(struct printbuf *out, struct bch_fs *c)
 {
 	struct bch_fs_rebalance *r = &c->rebalance;
 	struct rebalance_work w = rebalance_work(c);
-	char h1[21], h2[21];
 
-	bch2_hprint(&PBUF(h1), w.dev_most_full_work << 9);
-	bch2_hprint(&PBUF(h2), w.dev_most_full_capacity << 9);
-	pr_buf(out, "fullest_dev (%i):\t%s/%s\n",
-	       w.dev_most_full_idx, h1, h2);
+	out->tabstops[0] = 20;
 
-	bch2_hprint(&PBUF(h1), w.total_work << 9);
-	bch2_hprint(&PBUF(h2), c->capacity << 9);
-	pr_buf(out, "total work:\t\t%s/%s\n", h1, h2);
+	pr_buf(out, "fullest_dev (%i):", w.dev_most_full_idx);
+	pr_tab(out);
 
-	pr_buf(out, "rate:\t\t\t%u\n", r->pd.rate.rate);
+	bch2_hprint(out, w.dev_most_full_work << 9);
+	pr_buf(out, "/");
+	bch2_hprint(out, w.dev_most_full_capacity << 9);
+	pr_newline(out);
+
+	pr_buf(out, "total work:");
+	pr_tab(out);
+
+	bch2_hprint(out, w.total_work << 9);
+	pr_buf(out, "/");
+	bch2_hprint(out, c->capacity << 9);
+	pr_newline(out);
+
+	pr_buf(out, "rate:");
+	pr_tab(out);
+	pr_buf(out, "%u", r->pd.rate.rate);
+	pr_newline(out);
 
 	switch (r->state) {
 	case REBALANCE_WAITING:
-		pr_buf(out, "waiting\n");
+		pr_buf(out, "waiting");
 		break;
 	case REBALANCE_THROTTLED:
-		bch2_hprint(&PBUF(h1),
+		pr_buf(out, "throttled for %lu sec or ",
+		       (r->throttled_until_cputime - jiffies) / HZ);
+		bch2_hprint(out,
 			    (r->throttled_until_iotime -
 			     atomic64_read(&c->io_clock[WRITE].now)) << 9);
-		pr_buf(out, "throttled for %lu sec or %s io\n",
-		       (r->throttled_until_cputime - jiffies) / HZ,
-		       h1);
+		pr_buf(out, " io");
 		break;
 	case REBALANCE_RUNNING:
-		pr_buf(out, "running\n");
+		pr_buf(out, "running");
 		break;
 	}
+	pr_newline(out);
 }
 
 void bch2_rebalance_stop(struct bch_fs *c)
diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index ae9ae1c7138c..6c4ffc5abdc5 100644
--- a/fs/bcachefs/recovery.c
+++ b/fs/bcachefs/recovery.c
@@ -760,6 +760,8 @@ static int verify_superblock_clean(struct bch_fs *c,
 {
 	unsigned i;
 	struct bch_sb_field_clean *clean = *cleanp;
+	struct printbuf buf1 = PRINTBUF;
+	struct printbuf buf2 = PRINTBUF;
 	int ret = 0;
 
 	if (mustfix_fsck_err_on(j->seq != clean->journal_seq, c,
@@ -772,7 +774,6 @@ static int verify_superblock_clean(struct bch_fs *c,
 	}
 
 	for (i = 0; i < BTREE_ID_NR; i++) {
-		char buf1[200], buf2[200];
 		struct bkey_i *k1, *k2;
 		unsigned l1 = 0, l2 = 0;
 
@@ -782,6 +783,19 @@ static int verify_superblock_clean(struct bch_fs *c,
 		if (!k1 && !k2)
 			continue;
 
+		printbuf_reset(&buf1);
+		printbuf_reset(&buf2);
+
+		if (k1)
+			bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(k1));
+		else
+			pr_buf(&buf1, "(none)");
+
+		if (k2)
+			bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(k2));
+		else
+			pr_buf(&buf2, "(none)");
+
 		mustfix_fsck_err_on(!k1 || !k2 ||
 				    IS_ERR(k1) ||
 				    IS_ERR(k2) ||
@@ -791,10 +805,12 @@ static int verify_superblock_clean(struct bch_fs *c,
 			"superblock btree root %u doesn't match journal after clean shutdown\n"
 			"sb:      l=%u %s\n"
 			"journal: l=%u %s\n", i,
-			l1, (bch2_bkey_val_to_text(&PBUF(buf1), c, bkey_i_to_s_c(k1)), buf1),
-			l2, (bch2_bkey_val_to_text(&PBUF(buf2), c, bkey_i_to_s_c(k2)), buf2));
+			l1, buf1.buf,
+			l2, buf2.buf);
 	}
 fsck_err:
+	printbuf_exit(&buf2);
+	printbuf_exit(&buf1);
 	return ret;
 }
 
diff --git a/fs/bcachefs/replicas.c b/fs/bcachefs/replicas.c
index 7cc2414893fc..e26642c01fd7 100644
--- a/fs/bcachefs/replicas.c
+++ b/fs/bcachefs/replicas.c
@@ -997,11 +997,12 @@ bool bch2_have_enough_devs(struct bch_fs *c, struct bch_devs_mask devs,
 
 		if (dflags & ~flags) {
 			if (print) {
-				char buf[100];
+				struct printbuf buf = PRINTBUF;
 
-				bch2_replicas_entry_to_text(&PBUF(buf), e);
+				bch2_replicas_entry_to_text(&buf, e);
 				bch_err(c, "insufficient devices online (%u) for replicas entry %s",
-					nr_online, buf);
+					nr_online, buf.buf);
+				printbuf_exit(&buf);
 			}
 			ret = false;
 			break;
diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
index 47eeb48c8c60..c616ce5ed194 100644
--- a/fs/bcachefs/super-io.c
+++ b/fs/bcachefs/super-io.c
@@ -572,16 +572,10 @@ int bch2_read_super(const char *path, struct bch_opts *opts,
 {
 	u64 offset = opt_get(*opts, sb);
 	struct bch_sb_layout layout;
-	char *_err;
-	struct printbuf err;
+	struct printbuf err = PRINTBUF;
 	__le64 *i;
 	int ret;
 
-	_err = kmalloc(4096, GFP_KERNEL);
-	if (!_err)
-		return -ENOMEM;
-	err = _PBUF(_err, 4096);
-
 	pr_verbose_init(*opts, "");
 
 	memset(sb, 0, sizeof(*sb));
@@ -633,8 +627,8 @@ int bch2_read_super(const char *path, struct bch_opts *opts,
 		goto err;
 
 	printk(KERN_ERR "bcachefs (%s): error reading default superblock: %s",
-	       path, _err);
-	err = _PBUF(_err, 4096);
+	       path, err.buf);
+	printbuf_reset(&err);
 
 	/*
 	 * Error reading primary superblock - read location of backup
@@ -689,16 +683,16 @@ got_super:
 	ret = bch2_sb_validate(sb, &err);
 	if (ret) {
 		printk(KERN_ERR "bcachefs (%s): error validating superblock: %s",
-		       path, _err);
+		       path, err.buf);
 		goto err_no_print;
 	}
 out:
 	pr_verbose_init(*opts, "ret %i", ret);
-	kfree(_err);
+	printbuf_exit(&err);
 	return ret;
 err:
 	printk(KERN_ERR "bcachefs (%s): error reading superblock: %s",
-	       path, _err);
+	       path, err.buf);
 err_no_print:
 	bch2_free_super(sb);
 	goto out;
@@ -768,6 +762,7 @@ int bch2_write_super(struct bch_fs *c)
 {
 	struct closure *cl = &c->sb_write;
 	struct bch_dev *ca;
+	struct printbuf err = PRINTBUF;
 	unsigned i, sb = 0, nr_wrote;
 	struct bch_devs_mask sb_written;
 	bool wrote, can_mount_without_written, can_mount_with_written;
@@ -795,18 +790,11 @@ int bch2_write_super(struct bch_fs *c)
 		bch2_sb_from_fs(c, ca);
 
 	for_each_online_member(ca, c, i) {
-		struct printbuf buf = { NULL, NULL };
+		printbuf_reset(&err);
 
-		ret = bch2_sb_validate(&ca->disk_sb, &buf);
+		ret = bch2_sb_validate(&ca->disk_sb, &err);
 		if (ret) {
-			char *_buf = kmalloc(4096, GFP_NOFS);
-			if (_buf) {
-				buf = _PBUF(_buf, 4096);
-				bch2_sb_validate(&ca->disk_sb, &buf);
-			}
-
-			bch2_fs_inconsistent(c, "sb invalid before write: %s", _buf);
-			kfree(_buf);
+			bch2_fs_inconsistent(c, "sb invalid before write: %s", err.buf);
 			percpu_ref_put(&ca->io_ref);
 			goto out;
 		}
@@ -897,6 +885,7 @@ int bch2_write_super(struct bch_fs *c)
 out:
 	/* Make new options visible after they're persistent: */
 	bch2_sb_update(c);
+	printbuf_exit(&err);
 	return ret;
 }
 
diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index d9b69c4244d5..27716d6e962d 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -870,12 +870,9 @@ noinline_for_stack
 static void print_mount_opts(struct bch_fs *c)
 {
 	enum bch_opt_id i;
-	char buf[512];
-	struct printbuf p = PBUF(buf);
+	struct printbuf p = PRINTBUF;
 	bool first = true;
 
-	strcpy(buf, "(null)");
-
 	if (c->opts.read_only) {
 		pr_buf(&p, "ro");
 		first = false;
@@ -897,7 +894,11 @@ static void print_mount_opts(struct bch_fs *c)
 		bch2_opt_to_text(&p, c, opt, v, OPT_SHOW_MOUNT_STYLE);
 	}
 
-	bch_info(c, "mounted with opts: %s", buf);
+	if (!p.pos)
+		pr_buf(&p, "(null)");
+
+	bch_info(c, "mounted with opts: %s", p.buf);
+	printbuf_exit(&p);
 }
 
 int bch2_fs_start(struct bch_fs *c)
@@ -1561,11 +1562,11 @@ int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
 
 	data = bch2_dev_has_data(c, ca);
 	if (data) {
-		char data_has_str[100];
+		struct printbuf data_has = PRINTBUF;
 
-		bch2_flags_to_text(&PBUF(data_has_str),
-				   bch2_data_types, data);
-		bch_err(ca, "Remove failed, still has data (%s)", data_has_str);
+		bch2_flags_to_text(&data_has, bch2_data_types, data);
+		bch_err(ca, "Remove failed, still has data (%s)", data_has.buf);
+		printbuf_exit(&data_has);
 		ret = -EBUSY;
 		goto err;
 	}
@@ -1614,16 +1615,9 @@ int bch2_dev_add(struct bch_fs *c, const char *path)
 	struct bch_sb_field_members *mi;
 	struct bch_member dev_mi;
 	unsigned dev_idx, nr_devices, u64s;
-	char *_errbuf;
-	struct printbuf errbuf;
+	struct printbuf errbuf = PRINTBUF;
 	int ret;
 
-	_errbuf = kmalloc(4096, GFP_KERNEL);
-	if (!_errbuf)
-		return -ENOMEM;
-
-	errbuf = _PBUF(_errbuf, 4096);
-
 	ret = bch2_read_super(path, &opts, &sb);
 	if (ret) {
 		bch_err(c, "device add error: error reading super: %i", ret);
@@ -1741,7 +1735,7 @@ err:
 	if (ca)
 		bch2_dev_free(ca);
 	bch2_free_super(&sb);
-	kfree(_errbuf);
+	printbuf_exit(&errbuf);
 	return ret;
 err_late:
 	up_write(&c->state_lock);
@@ -1906,8 +1900,7 @@ struct bch_fs *bch2_fs_open(char * const *devices, unsigned nr_devices,
 	struct bch_sb_field_members *mi;
 	unsigned i, best_sb = 0;
 	const char *err;
-	char *_errbuf = NULL;
-	struct printbuf errbuf;
+	struct printbuf errbuf = PRINTBUF;
 	int ret = 0;
 
 	if (!try_module_get(THIS_MODULE))
@@ -1920,14 +1913,6 @@ struct bch_fs *bch2_fs_open(char * const *devices, unsigned nr_devices,
 		goto err;
 	}
 
-	_errbuf = kmalloc(4096, GFP_KERNEL);
-	if (!_errbuf) {
-		ret = -ENOMEM;
-		goto err;
-	}
-
-	errbuf = _PBUF(_errbuf, 4096);
-
 	sb = kcalloc(nr_devices, sizeof(*sb), GFP_KERNEL);
 	if (!sb) {
 		ret = -ENOMEM;
@@ -1991,7 +1976,7 @@ struct bch_fs *bch2_fs_open(char * const *devices, unsigned nr_devices,
 	}
 out:
 	kfree(sb);
-	kfree(_errbuf);
+	printbuf_exit(&errbuf);
 	module_put(THIS_MODULE);
 	pr_verbose_init(opts, "ret %i", PTR_ERR_OR_ZERO(c));
 	return c;
diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index 1a3068f658a1..ce32b9068518 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -46,8 +46,28 @@ struct sysfs_ops type ## _sysfs_ops = {					\
 }
 
 #define SHOW(fn)							\
+static ssize_t fn ## _to_text(struct printbuf *,			\
+			      struct kobject *, struct attribute *);\
+									\
 static ssize_t fn ## _show(struct kobject *kobj, struct attribute *attr,\
 			   char *buf)					\
+{									\
+	struct printbuf out = PRINTBUF;					\
+	ssize_t ret = fn ## _to_text(&out, kobj, attr);			\
+									\
+	if (!ret && out.allocation_failure)				\
+		ret = -ENOMEM;						\
+									\
+	if (!ret) {							\
+		ret = min_t(size_t, out.pos, PAGE_SIZE - 1);		\
+		memcpy(buf, out.buf, ret);				\
+	}								\
+	printbuf_exit(&out);						\
+	return ret;							\
+}									\
+									\
+static ssize_t fn ## _to_text(struct printbuf *out, struct kobject *kobj,\
+			      struct attribute *attr)
 
 #define STORE(fn)							\
 static ssize_t fn ## _store(struct kobject *kobj, struct attribute *attr,\
@@ -64,22 +84,19 @@ static ssize_t fn ## _store(struct kobject *kobj, struct attribute *attr,\
 #define sysfs_printf(file, fmt, ...)					\
 do {									\
 	if (attr == &sysfs_ ## file)					\
-		return scnprintf(buf, PAGE_SIZE, fmt "\n", __VA_ARGS__);\
+		pr_buf(out, fmt "\n", __VA_ARGS__);			\
 } while (0)
 
 #define sysfs_print(file, var)						\
 do {									\
 	if (attr == &sysfs_ ## file)					\
-		return snprint(buf, PAGE_SIZE, var);			\
+		snprint(out, var);					\
 } while (0)
 
 #define sysfs_hprint(file, val)						\
 do {									\
-	if (attr == &sysfs_ ## file) {					\
-		bch2_hprint(&out, val);					\
-		pr_buf(&out, "\n");					\
-		return out.pos - buf;					\
-	}								\
+	if (attr == &sysfs_ ## file)					\
+		bch2_hprint(out, val);					\
 } while (0)
 
 #define var_printf(_var, fmt)	sysfs_printf(_var, fmt, var(_var))
@@ -348,7 +365,6 @@ static void bch2_gc_gens_pos_to_text(struct printbuf *out, struct bch_fs *c)
 SHOW(bch2_fs)
 {
 	struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
-	struct printbuf out = _PBUF(buf, PAGE_SIZE);
 
 	sysfs_print(minor,			c->minor);
 	sysfs_printf(internal_uuid, "%pU",	c->sb.uuid.b);
@@ -365,10 +381,8 @@ SHOW(bch2_fs)
 
 	sysfs_printf(btree_gc_periodic, "%u",	(int) c->btree_gc_periodic);
 
-	if (attr == &sysfs_gc_gens_pos) {
-		bch2_gc_gens_pos_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_gc_gens_pos)
+		bch2_gc_gens_pos_to_text(out, c);
 
 	sysfs_printf(copy_gc_enabled, "%i", c->copy_gc_enabled);
 
@@ -378,83 +392,54 @@ SHOW(bch2_fs)
 		     max(0LL, c->copygc_wait -
 			 atomic64_read(&c->io_clock[WRITE].now)) << 9);
 
-	if (attr == &sysfs_rebalance_work) {
-		bch2_rebalance_work_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_rebalance_work)
+		bch2_rebalance_work_to_text(out, c);
 
 	sysfs_print(promote_whole_extents,	c->promote_whole_extents);
 
 	/* Debugging: */
 
-	if (attr == &sysfs_journal_debug) {
-		bch2_journal_debug_to_text(&out, &c->journal);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_journal_debug)
+		bch2_journal_debug_to_text(out, &c->journal);
 
-	if (attr == &sysfs_journal_pins) {
-		bch2_journal_pins_to_text(&out, &c->journal);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_journal_pins)
+		bch2_journal_pins_to_text(out, &c->journal);
 
-	if (attr == &sysfs_btree_updates) {
-		bch2_btree_updates_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_btree_updates)
+		bch2_btree_updates_to_text(out, c);
 
-	if (attr == &sysfs_dirty_btree_nodes) {
-		bch2_dirty_btree_nodes_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_dirty_btree_nodes)
+		bch2_dirty_btree_nodes_to_text(out, c);
 
-	if (attr == &sysfs_btree_cache) {
-		bch2_btree_cache_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_btree_cache)
+		bch2_btree_cache_to_text(out, c);
 
-	if (attr == &sysfs_btree_key_cache) {
-		bch2_btree_key_cache_to_text(&out, &c->btree_key_cache);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_btree_key_cache)
+		bch2_btree_key_cache_to_text(out, &c->btree_key_cache);
 
-	if (attr == &sysfs_btree_transactions) {
-		bch2_btree_trans_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_btree_transactions)
+		bch2_btree_trans_to_text(out, c);
 
-	if (attr == &sysfs_stripes_heap) {
-		bch2_stripes_heap_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_stripes_heap)
+		bch2_stripes_heap_to_text(out, c);
 
-	if (attr == &sysfs_open_buckets) {
-		bch2_open_buckets_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_open_buckets)
+		bch2_open_buckets_to_text(out, c);
 
-	if (attr == &sysfs_compression_stats) {
-		bch2_compression_stats_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_compression_stats)
+		bch2_compression_stats_to_text(out, c);
 
-	if (attr == &sysfs_new_stripes) {
-		bch2_new_stripes_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_new_stripes)
+		bch2_new_stripes_to_text(out, c);
 
-	if (attr == &sysfs_io_timers_read) {
-		bch2_io_timers_to_text(&out, &c->io_clock[READ]);
-		return out.pos - buf;
-	}
-	if (attr == &sysfs_io_timers_write) {
-		bch2_io_timers_to_text(&out, &c->io_clock[WRITE]);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_io_timers_read)
+		bch2_io_timers_to_text(out, &c->io_clock[READ]);
 
-	if (attr == &sysfs_data_jobs) {
-		data_progress_to_text(&out, c);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_io_timers_write)
+		bch2_io_timers_to_text(out, &c->io_clock[WRITE]);
+
+	if (attr == &sysfs_data_jobs)
+		data_progress_to_text(out, c);
 
 	return 0;
 }
@@ -567,7 +552,7 @@ struct attribute *bch2_fs_files[] = {
 SHOW(bch2_fs_internal)
 {
 	struct bch_fs *c = container_of(kobj, struct bch_fs, internal);
-	return bch2_fs_show(&c->kobj, attr, buf);
+	return bch2_fs_to_text(out, &c->kobj, attr);
 }
 
 STORE(bch2_fs_internal)
@@ -617,16 +602,15 @@ struct attribute *bch2_fs_internal_files[] = {
 
 SHOW(bch2_fs_opts_dir)
 {
-	struct printbuf out = _PBUF(buf, PAGE_SIZE);
 	struct bch_fs *c = container_of(kobj, struct bch_fs, opts_dir);
 	const struct bch_option *opt = container_of(attr, struct bch_option, attr);
 	int id = opt - bch2_opt_table;
 	u64 v = bch2_opt_get_by_id(&c->opts, id);
 
-	bch2_opt_to_text(&out, c, opt, v, OPT_SHOW_FULL_LIST);
-	pr_buf(&out, "\n");
+	bch2_opt_to_text(out, c, opt, v, OPT_SHOW_FULL_LIST);
+	pr_char(out, '\n');
 
-	return out.pos - buf;
+	return 0;
 }
 
 STORE(bch2_fs_opts_dir)
@@ -690,13 +674,10 @@ int bch2_opts_create_sysfs_files(struct kobject *kobj)
 SHOW(bch2_fs_time_stats)
 {
 	struct bch_fs *c = container_of(kobj, struct bch_fs, time_stats);
-	struct printbuf out = _PBUF(buf, PAGE_SIZE);
 
 #define x(name)								\
-	if (attr == &sysfs_time_stat_##name) {				\
-		bch2_time_stats_to_text(&out, &c->times[BCH_TIME_##name]);\
-		return out.pos - buf;					\
-	}
+	if (attr == &sysfs_time_stat_##name)				\
+		bch2_time_stats_to_text(out, &c->times[BCH_TIME_##name]);
 	BCH_TIME_STATS()
 #undef x
 
@@ -812,7 +793,6 @@ SHOW(bch2_dev)
 {
 	struct bch_dev *ca = container_of(kobj, struct bch_dev, kobj);
 	struct bch_fs *c = ca->fs;
-	struct printbuf out = _PBUF(buf, PAGE_SIZE);
 
 	sysfs_printf(uuid,		"%pU\n", ca->uuid.b);
 
@@ -825,58 +805,47 @@ SHOW(bch2_dev)
 	if (attr == &sysfs_label) {
 		if (ca->mi.group) {
 			mutex_lock(&c->sb_lock);
-			bch2_disk_path_to_text(&out, c->disk_sb.sb,
+			bch2_disk_path_to_text(out, c->disk_sb.sb,
 					       ca->mi.group - 1);
 			mutex_unlock(&c->sb_lock);
 		}
 
-		pr_buf(&out, "\n");
-		return out.pos - buf;
+		pr_char(out, '\n');
 	}
 
 	if (attr == &sysfs_has_data) {
-		bch2_flags_to_text(&out, bch2_data_types,
+		bch2_flags_to_text(out, bch2_data_types,
 				   bch2_dev_has_data(c, ca));
-		pr_buf(&out, "\n");
-		return out.pos - buf;
+		pr_char(out, '\n');
 	}
 
 	if (attr == &sysfs_state_rw) {
-		bch2_string_opt_to_text(&out, bch2_member_states,
+		bch2_string_opt_to_text(out, bch2_member_states,
 					ca->mi.state);
-		pr_buf(&out, "\n");
-		return out.pos - buf;
+		pr_char(out, '\n');
 	}
 
-	if (attr == &sysfs_iodone) {
-		dev_iodone_to_text(&out, ca);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_iodone)
+		dev_iodone_to_text(out, ca);
 
 	sysfs_print(io_latency_read,		atomic64_read(&ca->cur_latency[READ]));
 	sysfs_print(io_latency_write,		atomic64_read(&ca->cur_latency[WRITE]));
 
-	if (attr == &sysfs_io_latency_stats_read) {
-		bch2_time_stats_to_text(&out, &ca->io_latency[READ]);
-		return out.pos - buf;
-	}
-	if (attr == &sysfs_io_latency_stats_write) {
-		bch2_time_stats_to_text(&out, &ca->io_latency[WRITE]);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_io_latency_stats_read)
+		bch2_time_stats_to_text(out, &ca->io_latency[READ]);
+
+	if (attr == &sysfs_io_latency_stats_write)
+		bch2_time_stats_to_text(out, &ca->io_latency[WRITE]);
 
 	sysfs_printf(congested,			"%u%%",
 		     clamp(atomic_read(&ca->congested), 0, CONGESTED_MAX)
 		     * 100 / CONGESTED_MAX);
 
-	if (attr == &sysfs_reserve_stats) {
-		reserve_stats_to_text(&out, ca);
-		return out.pos - buf;
-	}
-	if (attr == &sysfs_alloc_debug) {
-		dev_alloc_debug_to_text(&out, ca);
-		return out.pos - buf;
-	}
+	if (attr == &sysfs_reserve_stats)
+		reserve_stats_to_text(out, ca);
+
+	if (attr == &sysfs_alloc_debug)
+		dev_alloc_debug_to_text(out, ca);
 
 	return 0;
 }
diff --git a/fs/bcachefs/tests.c b/fs/bcachefs/tests.c
index 1f7f2533e544..978d92e0b5eb 100644
--- a/fs/bcachefs/tests.c
+++ b/fs/bcachefs/tests.c
@@ -871,7 +871,9 @@ int bch2_btree_perf_test(struct bch_fs *c, const char *testname,
 			 u64 nr, unsigned nr_threads)
 {
 	struct test_job j = { .c = c, .nr = nr, .nr_threads = nr_threads };
-	char name_buf[20], nr_buf[20], per_sec_buf[20];
+	char name_buf[20];
+	struct printbuf nr_buf = PRINTBUF;
+	struct printbuf per_sec_buf = PRINTBUF;
 	unsigned i;
 	u64 time;
 
@@ -932,13 +934,15 @@ int bch2_btree_perf_test(struct bch_fs *c, const char *testname,
 	time = j.finish - j.start;
 
 	scnprintf(name_buf, sizeof(name_buf), "%s:", testname);
-	bch2_hprint(&PBUF(nr_buf), nr);
-	bch2_hprint(&PBUF(per_sec_buf), div64_u64(nr * NSEC_PER_SEC, time));
+	bch2_hprint(&nr_buf, nr);
+	bch2_hprint(&per_sec_buf, div64_u64(nr * NSEC_PER_SEC, time));
 	printk(KERN_INFO "%-12s %s with %u threads in %5llu sec, %5llu nsec per iter, %5s per sec\n",
-		name_buf, nr_buf, nr_threads,
+		name_buf, nr_buf.buf, nr_threads,
 		div_u64(time, NSEC_PER_SEC),
 		div_u64(time * nr_threads, nr),
-		per_sec_buf);
+		per_sec_buf.buf);
+	printbuf_exit(&per_sec_buf);
+	printbuf_exit(&nr_buf);
 	return j.ret;
 }
 
diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index 2296658b9f0d..7a896ddc9a22 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -99,6 +99,38 @@ STRTO_H(strtoll, long long)
 STRTO_H(strtoull, unsigned long long)
 STRTO_H(strtou64, u64)
 
+static int bch2_printbuf_realloc(struct printbuf *out, unsigned extra)
+{
+	unsigned new_size = roundup_pow_of_two(out->size + extra);
+	char *buf = krealloc(out->buf, new_size, !out->atomic ? GFP_KERNEL : GFP_ATOMIC);
+
+	if (!buf) {
+		out->allocation_failure = true;
+		return -ENOMEM;
+	}
+
+	out->buf	= buf;
+	out->size	= new_size;
+	return 0;
+}
+
+void bch2_pr_buf(struct printbuf *out, const char *fmt, ...)
+{
+	va_list args;
+	int len;
+
+	do {
+		va_start(args, fmt);
+		len = vsnprintf(out->buf + out->pos, printbuf_remaining(out), fmt, args);
+		va_end(args);
+	} while (len + 1 >= printbuf_remaining(out) &&
+		 !bch2_printbuf_realloc(out, len + 1));
+
+	len = min_t(size_t, len,
+		  printbuf_remaining(out) ? printbuf_remaining(out) - 1 : 0);
+	out->pos += len;
+}
+
 void bch2_hprint(struct printbuf *buf, s64 v)
 {
 	int u, t = 0;
@@ -151,9 +183,6 @@ void bch2_flags_to_text(struct printbuf *out,
 	unsigned bit, nr = 0;
 	bool first = true;
 
-	if (out->pos != out->end)
-		*out->pos = '\0';
-
 	while (list[nr])
 		nr++;
 
diff --git a/fs/bcachefs/util.h b/fs/bcachefs/util.h
index 58427edcfaa4..7667944f9ae4 100644
--- a/fs/bcachefs/util.h
+++ b/fs/bcachefs/util.h
@@ -242,19 +242,39 @@ enum printbuf_units {
 };
 
 struct printbuf {
-	char			*pos;
-	char			*end;
-	char			*last_newline;
-	char			*last_field;
+	char			*buf;
+	unsigned		size;
+	unsigned		pos;
+	unsigned		last_newline;
+	unsigned		last_field;
 	unsigned		indent;
-	enum printbuf_units	units;
-	unsigned		tabstop;
-	unsigned		tabstops[4];
+	enum printbuf_units	units:8;
+	u8			atomic;
+	bool			allocation_failure:1;
+	u8			tabstop;
+	u8			tabstops[4];
 };
 
+#define PRINTBUF ((struct printbuf) { NULL })
+
+static inline void printbuf_exit(struct printbuf *buf)
+{
+	kfree(buf->buf);
+	buf->buf = ERR_PTR(-EINTR); /* poison value */
+}
+
+static inline void printbuf_reset(struct printbuf *buf)
+{
+	buf->pos		= 0;
+	buf->last_newline	= 0;
+	buf->last_field		= 0;
+	buf->indent		= 0;
+	buf->tabstop		= 0;
+}
+
 static inline size_t printbuf_remaining(struct printbuf *buf)
 {
-	return buf->end - buf->pos;
+	return buf->size - buf->pos;
 }
 
 static inline size_t printbuf_linelen(struct printbuf *buf)
@@ -262,29 +282,13 @@ static inline size_t printbuf_linelen(struct printbuf *buf)
 	return buf->pos - buf->last_newline;
 }
 
-#define _PBUF(_buf, _len)						\
-	((struct printbuf) {						\
-		.pos		= _buf,					\
-		.end		= _buf + _len,				\
-		.last_newline	= _buf,					\
-		.last_field	= _buf,					\
-	})
+void bch2_pr_buf(struct printbuf *out, const char *fmt, ...);
 
-#define PBUF(_buf) _PBUF(_buf, sizeof(_buf))
-
-
-#define pr_buf(_out, ...)						\
-do {									\
-	(_out)->pos += scnprintf((_out)->pos, printbuf_remaining(_out),	\
-				 __VA_ARGS__);				\
-} while (0)
+#define pr_buf(_out, ...) bch2_pr_buf(_out, __VA_ARGS__)
 
 static inline void pr_char(struct printbuf *out, char c)
 {
-	if (printbuf_remaining(out) > 1) {
-		*out->pos = c;
-		out->pos++;
-	}
+	bch2_pr_buf(out, "%c", c);
 }
 
 static inline void pr_indent_push(struct printbuf *buf, unsigned spaces)
@@ -298,7 +302,7 @@ static inline void pr_indent_pop(struct printbuf *buf, unsigned spaces)
 {
 	if (buf->last_newline + buf->indent == buf->pos) {
 		buf->pos -= spaces;
-		buf->pos = '\0';
+		buf->buf[buf->pos] = '\0';
 	}
 	buf->indent -= spaces;
 }
@@ -341,12 +345,12 @@ static inline void pr_tab_rjust(struct printbuf *buf)
 	BUG_ON(buf->tabstop > ARRAY_SIZE(buf->tabstops));
 
 	if (shift > 0) {
-		memmove(buf->last_field + shift,
-			buf->last_field,
+		memmove(buf->buf + buf->last_field + shift,
+			buf->buf + buf->last_field,
 			move);
-		memset(buf->last_field, ' ', shift);
+		memset(buf->buf + buf->last_field, ' ', shift);
 		buf->pos += shift;
-		*buf->pos = 0;
+		buf->buf[buf->pos] = 0;
 	}
 
 	buf->last_field = buf->pos;
@@ -460,8 +464,8 @@ static inline int bch2_strtoul_h(const char *cp, long *res)
 	_r;								\
 })
 
-#define snprint(buf, size, var)						\
-	snprintf(buf, size,						\
+#define snprint(out, var)						\
+	pr_buf(out,							\
 		   type_is(var, int)		? "%i\n"		\
 		 : type_is(var, unsigned)	? "%u\n"		\
 		 : type_is(var, long)		? "%li\n"		\
@@ -605,10 +609,8 @@ do {									\
 	sysfs_print(name##_rate_d_term,		(var)->d_term);		\
 	sysfs_print(name##_rate_p_term_inverse,	(var)->p_term_inverse);	\
 									\
-	if (attr == &sysfs_##name##_rate_debug) {			\
-		bch2_pd_controller_debug_to_text(&out, var);		\
-		return out.pos - buf;					\
-	}								\
+	if (attr == &sysfs_##name##_rate_debug)				\
+		bch2_pd_controller_debug_to_text(out, var);		\
 } while (0)
 
 #define sysfs_pd_controller_store(name, var)				\
diff --git a/fs/bcachefs/xattr.c b/fs/bcachefs/xattr.c
index 9cce3953ee0c..f4e20e796ba0 100644
--- a/fs/bcachefs/xattr.c
+++ b/fs/bcachefs/xattr.c
@@ -426,9 +426,8 @@ static int __bch2_xattr_bcachefs_get(const struct xattr_handler *handler,
 		bch2_inode_opts_to_opts(bch2_inode_opts_get(&inode->ei_inode));
 	const struct bch_option *opt;
 	int id, inode_opt_id;
-	char buf[512];
-	struct printbuf out = PBUF(buf);
-	unsigned val_len;
+	struct printbuf out = PRINTBUF;
+	int ret;
 	u64 v;
 
 	id = bch2_opt_lookup(name);
@@ -451,14 +450,19 @@ static int __bch2_xattr_bcachefs_get(const struct xattr_handler *handler,
 	v = bch2_opt_get_by_id(&opts, id);
 	bch2_opt_to_text(&out, c, opt, v, 0);
 
-	val_len = out.pos - buf;
+	ret = out.pos;
 
-	if (buffer && val_len > size)
-		return -ERANGE;
+	if (out.allocation_failure) {
+		ret = -ENOMEM;
+	} else if (buffer) {
+		if (out.pos > size)
+			ret = -ERANGE;
+		else
+			memcpy(buffer, out.buf, out.pos);
+	}
 
-	if (buffer)
-		memcpy(buffer, buf, val_len);
-	return val_len;
+	printbuf_exit(&out);
+	return ret;
 }
 
 static int bch2_xattr_bcachefs_get(const struct xattr_handler *handler,