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[PATCH v9 32/34] qcow2: Allow preallocation and backing files if extende
From: |
Alberto Garcia |
Subject: |
[PATCH v9 32/34] qcow2: Allow preallocation and backing files if extended_l2 is set |
Date: |
Sun, 28 Jun 2020 13:02:41 +0200 |
Traditional qcow2 images don't allow preallocation if a backing file
is set. This is because once a cluster is allocated there is no way to
tell that its data should be read from the backing file.
Extended L2 entries have individual allocation bits for each
subcluster, and therefore it is perfectly possible to have an
allocated cluster with all its subclusters unallocated.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
block/qcow2.c | 7 ++++---
tests/qemu-iotests/206.out | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 37bfae823c..1ea8d3b87e 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3451,10 +3451,11 @@ qcow2_co_create(BlockdevCreateOptions *create_options,
Error **errp)
qcow2_opts->preallocation = PREALLOC_MODE_OFF;
}
if (qcow2_opts->has_backing_file &&
- qcow2_opts->preallocation != PREALLOC_MODE_OFF)
+ qcow2_opts->preallocation != PREALLOC_MODE_OFF &&
+ !qcow2_opts->extended_l2)
{
- error_setg(errp, "Backing file and preallocation cannot be used at "
- "the same time");
+ error_setg(errp, "Backing file and preallocation can only be used at "
+ "the same time if extended_l2 is on");
ret = -EINVAL;
goto out;
}
diff --git a/tests/qemu-iotests/206.out b/tests/qemu-iotests/206.out
index 363c5abe35..a100849fcb 100644
--- a/tests/qemu-iotests/206.out
+++ b/tests/qemu-iotests/206.out
@@ -203,7 +203,7 @@ Job failed: Different refcount widths than 16 bits require
compatibility level 1
=== Invalid backing file options ===
{"execute": "blockdev-create", "arguments": {"job-id": "job0", "options":
{"backing-file": "/dev/null", "driver": "qcow2", "file": "node0",
"preallocation": "full", "size": 67108864}}}
{"return": {}}
-Job failed: Backing file and preallocation cannot be used at the same time
+Job failed: Backing file and preallocation can only be used at the same time
if extended_l2 is on
{"execute": "job-dismiss", "arguments": {"id": "job0"}}
{"return": {}}
--
2.20.1
- [PATCH v9 29/34] qcow2: Add subcluster support to qcow2_measure(), (continued)
- [PATCH v9 29/34] qcow2: Add subcluster support to qcow2_measure(), Alberto Garcia, 2020/06/28
- [PATCH v9 22/34] qcow2: Add subcluster support to zero_in_l2_slice(), Alberto Garcia, 2020/06/28
- [PATCH v9 25/34] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(), Alberto Garcia, 2020/06/28
- [PATCH v9 01/34] qcow2: Make Qcow2AioTask store the full host offset, Alberto Garcia, 2020/06/28
- [PATCH v9 33/34] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters, Alberto Garcia, 2020/06/28
- [PATCH v9 15/34] qcow2: Add qcow2_get_subcluster_range_type(), Alberto Garcia, 2020/06/28
- [PATCH v9 23/34] qcow2: Add subcluster support to discard_in_l2_slice(), Alberto Garcia, 2020/06/28
- [PATCH v9 20/34] qcow2: Add subcluster support to calculate_l2_meta(), Alberto Garcia, 2020/06/28
- [PATCH v9 27/34] qcow2: Add subcluster support to handle_alloc_space(), Alberto Garcia, 2020/06/28
- [PATCH v9 30/34] qcow2: Add prealloc field to QCowL2Meta, Alberto Garcia, 2020/06/28
- [PATCH v9 32/34] qcow2: Allow preallocation and backing files if extended_l2 is set,
Alberto Garcia <=
- [PATCH v9 18/34] qcow2: Replace QCOW2_CLUSTER_* with QCOW2_SUBCLUSTER_*, Alberto Garcia, 2020/06/28
- [PATCH v9 14/34] qcow2: Add QCow2SubclusterType and qcow2_get_subcluster_type(), Alberto Garcia, 2020/06/28
- [PATCH v9 12/34] qcow2: Add l2_entry_size(), Alberto Garcia, 2020/06/28
- [PATCH v9 17/34] qcow2: Add cluster type parameter to qcow2_get_host_offset(), Alberto Garcia, 2020/06/28
- [PATCH v9 28/34] qcow2: Add subcluster support to qcow2_co_pwrite_zeroes(), Alberto Garcia, 2020/06/28
- [PATCH v9 21/34] qcow2: Add subcluster support to qcow2_get_host_offset(), Alberto Garcia, 2020/06/28
- [PATCH v9 34/34] iotests: Add tests for qcow2 images with extended L2 entries, Alberto Garcia, 2020/06/28
- [PATCH v9 31/34] qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bit, Alberto Garcia, 2020/06/28