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block/iscsi: allow fall back to WRITE SAME without UNMAP

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if the iscsi driver receives a write zeroes request with
the BDRV_REQ_MAY_UNMAP flag set it fails with -ENOTSUP
if the iscsi target does not support WRITE SAME with
UNMAP. However, the BDRV_REQ_MAY_UNMAP is only a hint
and writing zeroes with WRITE SAME will still be
better than falling back to writing zeroes with WRITE16.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Lieven 2014-04-28 13:23:25 +02:00 committed by Paolo Bonzini
parent d383c625e2
commit dbe5c58f2a
1 changed files with 6 additions and 5 deletions
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11
block/iscsi.c
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@ -809,13 +809,14 @@ coroutine_fn iscsi_co_write_zeroes(BlockDriverState *bs, int64_t sector_num,
return -EINVAL;
}
if (!(flags & BDRV_REQ_MAY_UNMAP) && !iscsilun->has_write_same) {
/* WRITE SAME without UNMAP is not supported by the target */
return -ENOTSUP;
if ((flags & BDRV_REQ_MAY_UNMAP) && !iscsilun->lbp.lbpws) {
/* WRITE SAME with UNMAP is not supported by the target,
* fall back and try WRITE SAME without UNMAP */
flags &= ~BDRV_REQ_MAY_UNMAP;
}
if ((flags & BDRV_REQ_MAY_UNMAP) && !iscsilun->lbp.lbpws) {
/* WRITE SAME with UNMAP is not supported by the target */
if (!(flags & BDRV_REQ_MAY_UNMAP) && !iscsilun->has_write_same) {
/* WRITE SAME without UNMAP is not supported by the target */
return -ENOTSUP;
}