From d7dd3fb84f05a0d221be3979929706a4828fb252 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Sat, 7 Jan 2023 22:55:42 -0500
Subject: [PATCH] bcachefs: Fix rereplicate when we already have a cached
pointer
When we need to add more replicas to an extent, it might be the case
that we already have a replica on every device, but some of them are
cached.
This patch fixes a bug where we'd spin on that extent because the write
path fails to find a device we can allocate from: we allow allocating
from devices that already have cached replicas on them, and change
bch2_data_update_index_update() to drop the cached replica if needed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
fs/bcachefs/data_update.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/fs/bcachefs/data_update.c b/fs/bcachefs/data_update.c
index b4480852e935f..acb634b3480ba 100644
--- a/fs/bcachefs/data_update.c
+++ b/fs/bcachefs/data_update.c
@@ -183,7 +183,17 @@ int bch2_data_update_index_update(struct bch_write_op *op)
/* Add new ptrs: */
extent_for_each_ptr_decode(extent_i_to_s(new), p, entry) {
- if (bch2_bkey_has_device(bkey_i_to_s_c(insert), p.ptr.dev)) {
+ const struct bch_extent_ptr *existing_ptr =
+ bch2_bkey_has_device(bkey_i_to_s_c(insert), p.ptr.dev);
+
+ if (existing_ptr && existing_ptr->cached) {
+ /*
+ * We're replacing a cached pointer with a non
+ * cached pointer:
+ */
+ bch2_bkey_drop_device_noerror(bkey_i_to_s(insert),
+ existing_ptr->dev);
+ } else if (existing_ptr) {
/*
* raced with another move op? extent already
* has a pointer to the device we just wrote
@@ -334,7 +344,8 @@ int bch2_data_update_init(struct bch_fs *c, struct data_update *m,
p.ptr.cached)
BUG();
- if (!((1U << i) & m->data_opts.rewrite_ptrs))
+ if (!((1U << i) & m->data_opts.rewrite_ptrs) &&
+ !p.ptr.cached)
bch2_dev_list_add_dev(&m->op.devs_have, p.ptr.dev);
if (((1U << i) & m->data_opts.rewrite_ptrs) &&
--
2.30.2