On Mon, Jun 29, 2020 at 11:51:18AM +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 will still
> happen.
>
> This 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>
Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
> ---
> fs/iomap/apply.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
> index 76925b40b5fd..26ab6563181f 100644
> --- a/fs/iomap/apply.c
> +++ b/fs/iomap/apply.c
> @@ -46,10 +46,14 @@ 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)) {
> + written = -EIO;
> + goto out;
> + }
> + if (WARN_ON(iomap.length == 0)) {
> + written = -EIO;
> + goto out;
> + }
>
> trace_iomap_apply_dstmap(inode, &iomap);
> if (srcmap.type != IOMAP_HOLE)
> @@ -80,6 +84,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
> written = actor(inode, pos, length, data, &iomap,
> srcmap.type != IOMAP_HOLE ? &srcmap : &iomap);
>
> +out:
> /*
> * Now the data has been copied, commit the range we've copied. This
> * should not fail unless the filesystem has had a fatal error.
>
> base-commit: 69119673bd50b176ded34032fadd41530fb5af21
> --
> 2.26.2
>
