From f295920bc4a0f34f7c4182f53c8f0c929e4358a2 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Wed, 5 Jun 2024 12:35:48 -0400
Subject: [PATCH] bcachefs: Fix race in bch2_accounting_mem_insert()
bch2_accounting_mem_insert() drops and retakes mark_lock; thus, we need
to check if the entry in question has already been inserted.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
fs/bcachefs/disk_accounting.c | 14 ++++++++------
fs/bcachefs/disk_accounting.h | 14 +++++++++-----
2 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/fs/bcachefs/disk_accounting.c b/fs/bcachefs/disk_accounting.c
index 510ed683f0a0e..29bc4c816f95e 100644
--- a/fs/bcachefs/disk_accounting.c
+++ b/fs/bcachefs/disk_accounting.c
@@ -218,7 +218,7 @@ int bch2_accounting_update_sb(struct btree_trans *trans)
return 0;
}
-static int __bch2_accounting_mem_mod_slowpath(struct bch_fs *c, struct bkey_s_c_accounting a, bool gc)
+static int __bch2_accounting_mem_insert(struct bch_fs *c, struct bkey_s_c_accounting a, bool gc)
{
struct bch_replicas_padded r;
@@ -226,7 +226,12 @@ static int __bch2_accounting_mem_mod_slowpath(struct bch_fs *c, struct bkey_s_c_
!bch2_replicas_marked_locked(c, &r.e))
return -BCH_ERR_btree_insert_need_mark_replicas;
+ /* raced with another insert, already present: */
struct bch_accounting_mem *acc = &c->accounting[gc];
+ if (eytzinger0_find(acc->k.data, acc->k.nr, sizeof(acc->k.data[0]),
+ accounting_pos_cmp, &a.k->p) < acc->k.nr)
+ return 0;
+
unsigned new_nr_counters = acc->nr_counters + bch2_accounting_counters(a.k);
u64 __percpu *new_counters = __alloc_percpu_gfp(new_nr_counters * sizeof(u64),
@@ -256,17 +261,14 @@ static int __bch2_accounting_mem_mod_slowpath(struct bch_fs *c, struct bkey_s_c_
free_percpu(acc->v);
acc->v = new_counters;
acc->nr_counters = new_nr_counters;
-
- for (unsigned i = 0; i < n.nr_counters; i++)
- this_cpu_add(acc->v[n.offset + i], a.v->d[i]);
return 0;
}
-int bch2_accounting_mem_mod_slowpath(struct bch_fs *c, struct bkey_s_c_accounting a, bool gc)
+int bch2_accounting_mem_insert(struct bch_fs *c, struct bkey_s_c_accounting a, bool gc)
{
percpu_up_read(&c->mark_lock);
percpu_down_write(&c->mark_lock);
- int ret = __bch2_accounting_mem_mod_slowpath(c, a, gc);
+ int ret = __bch2_accounting_mem_insert(c, a, gc);
percpu_up_write(&c->mark_lock);
percpu_down_read(&c->mark_lock);
return ret;
diff --git a/fs/bcachefs/disk_accounting.h b/fs/bcachefs/disk_accounting.h
index ab1f74cb97c72..4b37f0c24b4ed 100644
--- a/fs/bcachefs/disk_accounting.h
+++ b/fs/bcachefs/disk_accounting.h
@@ -104,15 +104,19 @@ static inline int accounting_pos_cmp(const void *_l, const void *_r)
return bpos_cmp(*l, *r);
}
-int bch2_accounting_mem_mod_slowpath(struct bch_fs *, struct bkey_s_c_accounting, bool);
+int bch2_accounting_mem_insert(struct bch_fs *, struct bkey_s_c_accounting, bool);
static inline int __bch2_accounting_mem_mod(struct bch_fs *c, struct bkey_s_c_accounting a, bool gc)
{
struct bch_accounting_mem *acc = &c->accounting[gc];
- unsigned idx = eytzinger0_find(acc->k.data, acc->k.nr, sizeof(acc->k.data[0]),
- accounting_pos_cmp, &a.k->p);
- if (unlikely(idx >= acc->k.nr))
- return bch2_accounting_mem_mod_slowpath(c, a, gc);
+ unsigned idx;
+
+ while ((idx = eytzinger0_find(acc->k.data, acc->k.nr, sizeof(acc->k.data[0]),
+ accounting_pos_cmp, &a.k->p)) >= acc->k.nr) {
+ int ret = bch2_accounting_mem_insert(c, a, gc);
+ if (ret)
+ return ret;
+ }
unsigned offset = acc->k.data[idx].offset;
--
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