bcachefs: Fix an rcu splat

bch2_bucket_alloc() requires rcu_read_lock() to be held.

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

diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index 2c6aa36cc025a52f752b8a626dae54d9ab3035a0..27fcb378790b37d4f113c62f8c99a44555084354 100644 (file)
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -682,16 +682,19 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
        if (nr <= ja->nr)
                return 0;
 
-       ret = -ENOMEM;
        new_buckets     = kzalloc(nr * sizeof(u64), GFP_KERNEL);
        new_bucket_seq  = kzalloc(nr * sizeof(u64), GFP_KERNEL);
-       if (!new_buckets || !new_bucket_seq)
+       if (!new_buckets || !new_bucket_seq) {
+               ret = -ENOMEM;
                goto err;
+       }
 
        journal_buckets = bch2_sb_resize_journal(&ca->disk_sb,
                                        nr + sizeof(*journal_buckets) / sizeof(u64));
-       if (!journal_buckets)
+       if (!journal_buckets) {
+               ret = -ENOSPC;
                goto err;
+       }
 
        /*
         * We may be called from the device add path, before the new device has
@@ -720,8 +723,10 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
                                goto err;
                        }
                } else {
+                       rcu_read_lock();
                        ob = bch2_bucket_alloc(c, ca, RESERVE_ALLOC,
                                               false, cl);
+                       rcu_read_unlock();
                        if (IS_ERR(ob)) {
                                ret = cl ? -EAGAIN : -ENOSPC;
                                goto err;
@@ -773,8 +778,6 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
                if (!new_fs)
                        bch2_open_bucket_put(c, ob);
        }
-
-       ret = 0;
 err:
        bch2_sb_resize_journal(&ca->disk_sb,
                ja->nr + sizeof(*journal_buckets) / sizeof(u64));