On Tue, Oct 31, 2023 at 05:48:39PM -0400, John Stoffel wrote:
>
> Using latest HEAD from linux git (commit
> 5a6a09e97199d6600d31383055f9d43fbbcbe86f (HEAD -> master,
> origin/master, origin/HEAD), and the following config, I get this
> failure when compiling on x86_64 Debian Bullseye (11):
>
>
> CC fs/bcachefs/btree_io.o
> In file included from fs/bcachefs/btree_io.c:11:
> fs/bcachefs/btree_io.c: In function ‘bch2_btree_post_write_cleanup’:
> fs/bcachefs/btree_update_interior.h:274:36: error: array subscript 0 is outside the bounds of an interior zero-length array ‘struct bkey_packed[0]’ [-Werror=zero-length-bounds]
> 274 | __bch_btree_u64s_remaining(c, b, &bne->keys.start[0]);
> | ^~~~~~~~~~~~~~~~~~~
> In file included from fs/bcachefs/bcachefs.h:206,
> from fs/bcachefs/btree_io.c:3:
> fs/bcachefs/bcachefs_format.h:2344:21: note: while referencing ‘start’
> 2344 | struct bkey_packed start[0];
> | ^~~~~
> In file included from fs/bcachefs/btree_io.c:11:
> fs/bcachefs/btree_io.c: In function ‘bch2_btree_init_next’:
> fs/bcachefs/btree_update_interior.h:274:36: error: array subscript 0 is outside the bounds of an interior zero-length array ‘struct bkey_packed[0]’ [-Werror=zero-length-bounds]
> 274 | __bch_btree_u64s_remaining(c, b, &bne->keys.start[0]);
> | ^~~~~~~~~~~~~~~~~~~
> In file included from fs/bcachefs/bcachefs.h:206,
> from fs/bcachefs/btree_io.c:3:
> fs/bcachefs/bcachefs_format.h:2344:21: note: while referencing ‘start’
> 2344 | struct bkey_packed start[0];
> | ^~~~~
> cc1: all warnings being treated as errors
> make[4]: *** [scripts/Makefile.build:243: fs/bcachefs/btree_io.o] Error 1
> make[3]: *** [scripts/Makefile.build:480: fs/bcachefs] Error 2
> make[2]: *** [scripts/Makefile.build:480: fs] Error 2
> make[1]: *** [/local/src/kernel/git/linux/Makefile:1913: .] Error 2
> make: *** [Makefile:234: __sub-make] Error 2
It seems gcc 10 complains in situations gcc 11 does not.
I've got the following patch running through my testing automation now:
-- >8 --
From: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Date: Tue, 31 Oct 2023 18:05:22 -0400
Subject: [PATCH] bcachefs: Fix build errors with gcc 10
gcc 10 seems to complain about array bounds in situations where gcc 11
does not - curious.
This unfortunately requires adding some casts for now; we may
investigate getting rid of our __u64 _data[] VLA in a future patch so
that our start[0] members can be VLAs.
Reported-by: John Stoffel <john@xxxxxxxxxxx>
Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h
index 29b000c6b7e1..5b44598b9df9 100644
--- a/fs/bcachefs/bcachefs_format.h
+++ b/fs/bcachefs/bcachefs_format.h
@@ -1617,9 +1617,7 @@ struct journal_seq_blacklist_entry {
struct bch_sb_field_journal_seq_blacklist {
struct bch_sb_field field;
-
- struct journal_seq_blacklist_entry start[0];
- __u64 _data[];
+ struct journal_seq_blacklist_entry start[];
};
struct bch_sb_field_errors {
diff --git a/fs/bcachefs/btree_trans_commit.c b/fs/bcachefs/btree_trans_commit.c
index 8140b6e6e9a6..32693f7c6221 100644
--- a/fs/bcachefs/btree_trans_commit.c
+++ b/fs/bcachefs/btree_trans_commit.c
@@ -681,7 +681,7 @@ bch2_trans_commit_write_locked(struct btree_trans *trans, unsigned flags,
BCH_JSET_ENTRY_overwrite,
i->btree_id, i->level,
i->old_k.u64s);
- bkey_reassemble(&entry->start[0],
+ bkey_reassemble((struct bkey_i *) entry->start,
(struct bkey_s_c) { &i->old_k, i->old_v });
}
@@ -689,7 +689,7 @@ bch2_trans_commit_write_locked(struct btree_trans *trans, unsigned flags,
BCH_JSET_ENTRY_btree_keys,
i->btree_id, i->level,
i->k->k.u64s);
- bkey_copy(&entry->start[0], i->k);
+ bkey_copy((struct bkey_i *) entry->start, i->k);
}
trans_for_each_wb_update(trans, wb) {
@@ -697,7 +697,7 @@ bch2_trans_commit_write_locked(struct btree_trans *trans, unsigned flags,
BCH_JSET_ENTRY_btree_keys,
wb->btree, 0,
wb->k.k.u64s);
- bkey_copy(&entry->start[0], &wb->k);
+ bkey_copy((struct bkey_i *) entry->start, &wb->k);
}
if (trans->journal_seq)
diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index d029e0348c91..89ada89eafe7 100644
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -2411,7 +2411,7 @@ void bch2_journal_entry_to_btree_root(struct bch_fs *c, struct jset_entry *entry
r->level = entry->level;
r->alive = true;
- bkey_copy(&r->key, &entry->start[0]);
+ bkey_copy(&r->key, (struct bkey_i *) entry->start);
mutex_unlock(&c->btree_root_lock);
}
diff --git a/fs/bcachefs/btree_update_interior.h b/fs/bcachefs/btree_update_interior.h
index 5e0a467fe905..d92b3cf5f5e0 100644
--- a/fs/bcachefs/btree_update_interior.h
+++ b/fs/bcachefs/btree_update_interior.h
@@ -271,7 +271,7 @@ static inline struct btree_node_entry *want_new_bset(struct bch_fs *c,
struct btree_node_entry *bne = max(write_block(b),
(void *) btree_bkey_last(b, bset_tree_last(b)));
ssize_t remaining_space =
- __bch_btree_u64s_remaining(c, b, &bne->keys.start[0]);
+ __bch_btree_u64s_remaining(c, b, bne->keys.start);
if (unlikely(bset_written(b, bset(b, t)))) {
if (remaining_space > (ssize_t) (block_bytes(c) >> 3))
diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
index f73338f37bf1..9600b8083175 100644
--- a/fs/bcachefs/recovery.c
+++ b/fs/bcachefs/recovery.c
@@ -226,7 +226,7 @@ static int journal_replay_entry_early(struct bch_fs *c,
if (entry->u64s) {
r->level = entry->level;
- bkey_copy(&r->key, &entry->start[0]);
+ bkey_copy(&r->key, (struct bkey_i *) entry->start);
r->error = 0;
} else {
r->error = -EIO;
