Re: [PATCH] ksmbd: Do not skip lock checks for single-byte ranges

[Namjae Jeon]

On Sun, Jul 5, 2026 at 8:39 PM Guangshuo Li <lgs201920130244@xxxxxxxxx> wrote:
>
> check_lock_range() uses inclusive ranges. Its callers pass the end
> offset as start + length - 1, so start == end represents a valid
> single-byte range rather than an empty range.
>
> The start == end shortcut therefore skips mandatory byte-range lock
> checks for one-byte reads, writes, copychunk operations and one-byte
> truncate ranges. A conflicting lock covering that byte is not checked
> and the operation is allowed to proceed.
>
> Remove the shortcut. The truncate size == inode->i_size case is already
> handled by only calling check_lock_range() when the new size differs
> from the current file size.
>
> Fixes: 5d510ac31626 ("ksmbd: skip lock-range check on equal size to avoid size==0 underflow")
> Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
Applied it to #ksmbd-for-next-next.
Thanks!