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[Qemu-devel] [PATCH v14 06/14] block: Add backing_blocker in BlockDriver
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH v14 06/14] block: Add backing_blocker in BlockDriverState |
Date: |
Wed, 19 Feb 2014 21:42:23 +0800 |
This makes use of op_blocker and blocks all the operations except for
commit target, on each BlockDriverState->backing_hd.
The asserts for op_blocker in bdrv_swap are removed because with this
change, the target of block commit has at least the backing blocker of
its child, so the assertion is not true. Callers should do their check.
Signed-off-by: Fam Zheng <address@hidden>
---
block.c | 19 +++++++++++++++----
include/block/block_int.h | 3 +++
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/block.c b/block.c
index dec44d4..95d8c1f 100644
--- a/block.c
+++ b/block.c
@@ -1044,19 +1044,33 @@ fail:
void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
{
if (bs->backing_hd) {
+ assert(error_is_set(&bs->backing_blocker));
+ bdrv_op_unblock_all(bs->backing_hd, bs->backing_blocker);
bdrv_unref(bs->backing_hd);
+ } else if (backing_hd) {
+ error_setg(&bs->backing_blocker,
+ "device is used as backing hd of '%s'",
+ bs->device_name);
}
bs->backing_hd = backing_hd;
if (!backing_hd) {
bs->backing_file[0] = '\0';
bs->backing_format[0] = '\0';
+ if (error_is_set(&bs->backing_blocker)) {
+ error_free(bs->backing_blocker);
+ }
goto out;
}
pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
pstrcpy(bs->backing_format, sizeof(bs->backing_format),
backing_hd->drv ? backing_hd->drv->format_name : "");
bdrv_ref(bs->backing_hd);
+
+ bdrv_op_block_all(bs->backing_hd, bs->backing_blocker);
+ /* Otherwise we won't be able to commit due to check in bdrv_commit */
+ bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT,
+ bs->backing_blocker);
out:
bdrv_refresh_limits(bs);
}
@@ -1696,8 +1710,7 @@ void bdrv_close(BlockDriverState *bs)
if (bs->drv) {
if (bs->backing_hd) {
- bdrv_unref(bs->backing_hd);
- bs->backing_hd = NULL;
+ bdrv_set_backing_hd(bs, NULL);
}
bs->drv->bdrv_close(bs);
g_free(bs->opaque);
@@ -1899,7 +1912,6 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState
*bs_old)
assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
assert(bs_new->job == NULL);
assert(bs_new->dev == NULL);
- assert(bdrv_op_blocker_is_empty(bs_new));
assert(bs_new->io_limits_enabled == false);
assert(!throttle_have_timer(&bs_new->throttle_state));
@@ -1918,7 +1930,6 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState
*bs_old)
/* Check a few fields that should remain attached to the device */
assert(bs_new->dev == NULL);
assert(bs_new->job == NULL);
- assert(bdrv_op_blocker_is_empty(bs_new));
assert(bs_new->io_limits_enabled == false);
assert(!throttle_have_timer(&bs_new->throttle_state));
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 1d3f76f..1f4f78b 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -369,6 +369,9 @@ struct BlockDriverState {
BlockJob *job;
QDict *options;
+
+ /* The error object in use for blocking operations on backing_hd */
+ Error *backing_blocker;
};
int get_tmp_filename(char *filename, int size);
--
1.8.5.4
- [Qemu-devel] [PATCH v14 01/14] block: Add BlockOpType enum, (continued)
- [Qemu-devel] [PATCH v14 01/14] block: Add BlockOpType enum, Fam Zheng, 2014/02/19
- [Qemu-devel] [PATCH v14 02/14] block: Introduce op_blockers to BlockDriverState, Fam Zheng, 2014/02/19
- [Qemu-devel] [PATCH v14 03/14] block: Replace in_use with operation blocker, Fam Zheng, 2014/02/19
- [Qemu-devel] [PATCH v14 04/14] block: Move op_blocker check from block_job_create to its caller, Fam Zheng, 2014/02/19
- [Qemu-devel] [PATCH v14 05/14] block: Add bdrv_set_backing_hd(), Fam Zheng, 2014/02/19
- [Qemu-devel] [PATCH v14 06/14] block: Add backing_blocker in BlockDriverState,
Fam Zheng <=
[Qemu-devel] [PATCH v14 07/14] block: Parse "backing" option to reference existing BDS, Fam Zheng, 2014/02/19
[Qemu-devel] [PATCH v14 08/14] block: Support dropping active in bdrv_drop_intermediate, Fam Zheng, 2014/02/19