On Wed, 2019-09-18 at 11:51 +0200, Max Reitz wrote:
> We have two protocol drivers that return success when trying to shrink a
> block device even though they cannot shrink it. This behavior is now
> only allowed with exact=false, so they should return an error with
> exact=true.
>
> Signed-off-by: Max Reitz <mre...@redhat.com>
> ---
> block/file-posix.c | 8 +++++++-
> block/iscsi.c | 7 ++++++-
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index d8755c5fac..a85f3486d1 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -2028,6 +2028,7 @@ static int coroutine_fn
> raw_co_truncate(BlockDriverState *bs, int64_t offset,
> }
>
> if (S_ISREG(st.st_mode)) {
> + /* Always resizes to the exact @offset */
> return raw_regular_truncate(bs, s->fd, offset, prealloc, errp);
> }
>
> @@ -2038,7 +2039,12 @@ static int coroutine_fn
> raw_co_truncate(BlockDriverState *bs, int64_t offset,
> }
>
> if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
> - if (offset > raw_getlength(bs)) {
> + int64_t cur_length = raw_getlength(bs);
> +
> + if (offset != cur_length && exact) {
> + error_setg(errp, "Cannot resize device files");
> + return -ENOTSUP;
> + } else if (offset > cur_length) {
> error_setg(errp, "Cannot grow device files");
> return -EINVAL;
> }
> diff --git a/block/iscsi.c b/block/iscsi.c
> index a90426270a..cc2072ff6c 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -2126,6 +2126,7 @@ static int coroutine_fn
> iscsi_co_truncate(BlockDriverState *bs, int64_t offset,
> Error **errp)
> {
> IscsiLun *iscsilun = bs->opaque;
> + int64_t cur_length;
> Error *local_err = NULL;
>
> if (prealloc != PREALLOC_MODE_OFF) {
> @@ -2145,7 +2146,11 @@ static int coroutine_fn
> iscsi_co_truncate(BlockDriverState *bs, int64_t offset,
> return -EIO;
> }
>
> - if (offset > iscsi_getlength(bs)) {
> + cur_length = iscsi_getlength(bs);
> + if (offset != cur_length && exact) {
> + error_setg(errp, "Cannot resize iSCSI devices");
> + return -ENOTSUP;
> + } else if (offset > cur_length) {
> error_setg(errp, "Cannot grow iSCSI devices");
> return -EINVAL;
> }
Reviewed-by: Maxim Levitsky <mlevi...@redhat.com>
Best regards,
Maxim Levitsky
