block: Use common req handling for discard

Reuse the new bdrv_co_write_req_prepare/finish helpers. The variation
here is that discard requests don't affect bs->wr_highest_offset, and it
cannot extend the image.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2018-07-10 14:31:21 +08:00 committed by Kevin Wolf
parent 7f8f03ef6d
commit 00695c27a0

View File

@ -1623,15 +1623,32 @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
atomic_inc(&bs->write_gen);
stat64_max(&bs->wr_highest_offset, offset + bytes);
/*
* Discard cannot extend the image, but in error handling cases, such as
* when reverting a qcow2 cluster allocation, the discarded range can pass
* the end of image file, so we cannot assert about BDRV_TRACKED_DISCARD
* here. Instead, just skip it, since semantically a discard request
* beyond EOF cannot expand the image anyway.
*/
if (ret == 0 &&
end_sector > bs->total_sectors) {
end_sector > bs->total_sectors &&
req->type != BDRV_TRACKED_DISCARD) {
bs->total_sectors = end_sector;
bdrv_parent_cb_resize(bs);
bdrv_dirty_bitmap_truncate(bs, end_sector << BDRV_SECTOR_BITS);
}
bdrv_set_dirty(bs, offset, bytes);
if (req->bytes) {
switch (req->type) {
case BDRV_TRACKED_WRITE:
stat64_max(&bs->wr_highest_offset, offset + bytes);
/* fall through, to set dirty bits */
case BDRV_TRACKED_DISCARD:
bdrv_set_dirty(bs, offset, bytes);
break;
default:
break;
}
}
}
/*
@ -2692,10 +2709,7 @@ int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int bytes)
ret = bdrv_check_byte_request(bs, offset, bytes);
if (ret < 0) {
return ret;
} else if (bs->read_only) {
return -EPERM;
}
assert(!(bs->open_flags & BDRV_O_INACTIVE));
/* Do nothing if disabled. */
if (!(bs->open_flags & BDRV_O_UNMAP)) {
@ -2719,7 +2733,7 @@ int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int bytes)
bdrv_inc_in_flight(bs);
tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_DISCARD);
ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req);
ret = bdrv_co_write_req_prepare(child, offset, bytes, &req, 0);
if (ret < 0) {
goto out;
}
@ -2785,8 +2799,7 @@ int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int bytes)
}
ret = 0;
out:
atomic_inc(&bs->write_gen);
bdrv_set_dirty(bs, req.offset, req.bytes);
bdrv_co_write_req_finish(child, req.offset, req.bytes, &req, ret);
tracked_request_end(&req);
bdrv_dec_in_flight(bs);
return ret;