On Thu, Jun 18, 2020 at 02:24:08PM +0200, Andreas Gruenbacher wrote:
> Make sure iomap_end is always called when iomap_begin succeeds.
>
> Without this fix, iomap_end won't be called when a filesystem's
> iomap_begin operation returns an invalid mapping, bypassing any
> unlocking done in iomap_end. With this fix, the unlocking would
> at least still happen.
>
> This iomap_apply bug was found by Bob Peterson during code review.
> It's unlikely that such iomap_begin bugs will survive to affect
> users, so backporting this fix seems unnecessary.
>
> Fixes: ae259a9c8593 ("fs: introduce iomap infrastructure")
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> ---
> fs/iomap/apply.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
> index 76925b40b5fd..32daf8cb411c 100644
> --- a/fs/iomap/apply.c
> +++ b/fs/iomap/apply.c
> @@ -46,10 +46,11 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
> ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap);
> if (ret)
> return ret;
> - if (WARN_ON(iomap.offset > pos))
> - return -EIO;
> - if (WARN_ON(iomap.length == 0))
> - return -EIO;
> + if (WARN_ON(iomap.offset > pos) ||
> + WARN_ON(iomap.length == 0)) {
> + written = -EIO;
> + goto out;
> + }
As said before please don't merge these for no good reason.
