Re: [PATCH] bcachefs: replace deprecated strncpy() with strscpy()

[Kent Overstreet]

On Wed, Mar 26, 2025 at 06:02:31PM +0800, Alan Huang wrote:
> On Mar 26, 2025, at 17:44, Roxana Nicolescu <nicolescu.roxana@xxxxxxxxxxxxxx> wrote:
> > 
> > strncpy() is deprecated for NUL-terminated destination buffers. Use
> > strscpy() instead.
> > 
> > Link: https://github.com/KSPP/linux/issues/90
> > Signed-off-by: Roxana Nicolescu <nicolescu.roxana@xxxxxxxxxxxxxx>
> > ---
> > fs/bcachefs/btree_trans_commit.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/bcachefs/btree_trans_commit.c b/fs/bcachefs/btree_trans_commit.c
> > index c4f524b2ca9a..7ab25b425d11 100644
> > --- a/fs/bcachefs/btree_trans_commit.c
> > +++ b/fs/bcachefs/btree_trans_commit.c
> > @@ -364,7 +364,7 @@ static noinline void journal_transaction_name(struct btree_trans *trans)
> > struct jset_entry_log *l =
> > container_of(entry, struct jset_entry_log, entry);
> > 
> > - strncpy(l->d, trans->fn, JSET_ENTRY_LOG_U64s * sizeof(u64));
> > + strscpy(l->d, trans->fn, JSET_ENTRY_LOG_U64s * sizeof(u64));
> 
> The last time I asked Kent about this line, he didn’t want this.

Yes, the destination buffer isn't required to be nul terminated.

But it seems we should add a comment explaining that :)