Greg,
On Mon, Aug 17, 2020 at 6:06 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> From: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
>
> [ Upstream commit 856473cd5d17dbbf3055710857c67a4af6d9fcc0 ]
>
> 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.
as said for 5.7 / 5.8 already, this patch doesn't need to be backported.
Thanks,
Andreas
> Fixes: ae259a9c8593 ("fs: introduce iomap infrastructure")
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> 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 54c02aecf3cd8..c2281a6a7f320 100644
> --- a/fs/iomap/apply.c
> +++ b/fs/iomap/apply.c
> @@ -41,10 +41,14 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
> ret = ops->iomap_begin(inode, pos, length, flags, &iomap);
> 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;
> + }
>
> /*
> * Cut down the length to the one actually provided by the filesystem,
> @@ -60,6 +64,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
> */
> written = actor(inode, pos, length, data, &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.
> --
> 2.25.1
>
>
>
