On Thu, Nov 15, 2018 at 04:52:53PM +0800, Ming Lei wrote:
> Once multi-page bvec is enabled, the last bvec may include more than one
> page, this patch use bvec_last_segment() to truncate the bio.
>
> Cc: Dave Chinner <dchin...@redhat.com>
> Cc: Kent Overstreet <kent.overstr...@gmail.com>
> Cc: Mike Snitzer <snit...@redhat.com>
> Cc: dm-de...@redhat.com
> Cc: Alexander Viro <v...@zeniv.linux.org.uk>
> Cc: linux-fsde...@vger.kernel.org
> Cc: Shaohua Li <s...@kernel.org>
> Cc: linux-r...@vger.kernel.org
> Cc: linux-er...@lists.ozlabs.org
> Cc: David Sterba <dste...@suse.com>
> Cc: linux-btrfs@vger.kernel.org
> Cc: Darrick J. Wong <darrick.w...@oracle.com>
> Cc: linux-...@vger.kernel.org
> Cc: Gao Xiang <gaoxian...@huawei.com>
> Cc: Christoph Hellwig <h...@lst.de>
> Cc: Theodore Ts'o <ty...@mit.edu>
> Cc: linux-e...@vger.kernel.org
> Cc: Coly Li <col...@suse.de>
> Cc: linux-bca...@vger.kernel.org
> Cc: Boaz Harrosh <o...@electrozaur.com>
> Cc: Bob Peterson <rpete...@redhat.com>
> Cc: cluster-de...@redhat.com
Reviewed-by: Omar Sandoval <osan...@fb.com>
> Signed-off-by: Ming Lei <ming....@redhat.com>
> ---
> fs/buffer.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/buffer.c b/fs/buffer.c
> index 1286c2b95498..fa37ad52e962 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -3032,7 +3032,10 @@ void guard_bio_eod(int op, struct bio *bio)
>
> /* ..and clear the end of the buffer for reads */
> if (op == REQ_OP_READ) {
> - zero_user(bvec->bv_page, bvec->bv_offset + bvec->bv_len,
> + struct bio_vec bv;
> +
> + bvec_last_segment(bvec, &bv);
> + zero_user(bv.bv_page, bv.bv_offset + bv.bv_len,
> truncated_bytes);
> }
> }
> --
> 2.9.5
>
