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[Qemu-block] [PATCH 5/6] qcow2: Let vmstate call qcow2_co_preadv/pwrite
From: |
Kevin Wolf |
Subject: |
[Qemu-block] [PATCH 5/6] qcow2: Let vmstate call qcow2_co_preadv/pwrite directly |
Date: |
Fri, 10 Jun 2016 18:05:21 +0200 |
We don't really want to go through the block layer in order to read from
or write to the vmstate in a qcow2 image. Doing so required a few ugly
hacks like saving and restoring the old image size (because writing to
vmstate offsets would increase the image size) or disabling the "reads
after EOF = zeroes" logic. When calling the right functions directly,
these hacks aren't necessary any more.
Note that .bdrv_vmstate_load/save() return 0 instead of the number of
bytes in case of success now.
Signed-off-by: Kevin Wolf <address@hidden>
---
block/qcow2.c | 24 ++++--------------------
1 file changed, 4 insertions(+), 20 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 72ae2bf..c40baca 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2903,36 +2903,20 @@ static int qcow2_save_vmstate(BlockDriverState *bs,
QEMUIOVector *qiov,
int64_t pos)
{
BDRVQcow2State *s = bs->opaque;
- int64_t total_sectors = bs->total_sectors;
- bool zero_beyond_eof = bs->zero_beyond_eof;
- int ret;
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
- bs->zero_beyond_eof = false;
- ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov);
- bs->zero_beyond_eof = zero_beyond_eof;
-
- /* bdrv_co_do_writev will have increased the total_sectors value to include
- * the VM state - the VM state is however not an actual part of the block
- * device, therefore, we need to restore the old value. */
- bs->total_sectors = total_sectors;
-
- return ret;
+ return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos,
+ qiov->size, qiov, 0);
}
static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
int64_t pos)
{
BDRVQcow2State *s = bs->opaque;
- bool zero_beyond_eof = bs->zero_beyond_eof;
- int ret;
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
- bs->zero_beyond_eof = false;
- ret = bdrv_preadv(bs, qcow2_vm_state_offset(s) + pos, qiov);
- bs->zero_beyond_eof = zero_beyond_eof;
-
- return ret;
+ return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos,
+ qiov->size, qiov, 0);
}
/*
--
1.8.3.1
- [Qemu-block] [PATCH 0/6] block: bdrv_load/save_vmstate() cleanups, Kevin Wolf, 2016/06/10
- [Qemu-block] [PATCH 6/6] block: Remove bs->zero_beyond_eof, Kevin Wolf, 2016/06/10
- Re: [Qemu-block] [PATCH 0/6] block: bdrv_load/save_vmstate() cleanups, Fam Zheng, 2016/06/11
- Re: [Qemu-block] [PATCH 0/6] block: bdrv_load/save_vmstate() cleanups, Stefan Hajnoczi, 2016/06/16
- Re: [Qemu-block] [PATCH 0/6] block: bdrv_load/save_vmstate() cleanups, Kevin Wolf, 2016/06/16