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| author | Max Reitz <mreitz@redhat.com> | 2019-07-24 19:12:34 +0200 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2019-08-19 17:13:26 +0200 |
| commit | 38841dcd27a41e2d8916b7cf4f508a5663f453ff (patch) | |
| tree | 217862f70b3fed2b826bd4639c45db2b5c6b35e0 /block | |
| parent | b647d69adc394312dedb56f6b3ce19b9c316931f (diff) | |
| download | qemu-38841dcd27a41e2d8916b7cf4f508a5663f453ff.zip qemu-38841dcd27a41e2d8916b7cf4f508a5663f453ff.tar.gz qemu-38841dcd27a41e2d8916b7cf4f508a5663f453ff.tar.bz2 | |
qcow2: Fix .bdrv_has_zero_init()
If a qcow2 file is preallocated, it can no longer guarantee that it
initially appears as filled with zeroes.
So implement .bdrv_has_zero_init() by checking whether the file is
preallocated; if so, forward the call to the underlying storage node,
except for when it is encrypted: Encrypted preallocated images always
return effectively random data, so .bdrv_has_zero_init() must always
return 0 for them.
.bdrv_has_zero_init_truncate() can remain bdrv_has_zero_init_1(),
because it presupposes PREALLOC_MODE_OFF.
Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190724171239.8764-7-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/qcow2.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index ea3b42f..7c5a485 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -4632,6 +4632,33 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs, return spec_info; } +static int qcow2_has_zero_init(BlockDriverState *bs) +{ + BDRVQcow2State *s = bs->opaque; + bool preallocated; + + if (qemu_in_coroutine()) { + qemu_co_mutex_lock(&s->lock); + } + /* + * Check preallocation status: Preallocated images have all L2 + * tables allocated, nonpreallocated images have none. It is + * therefore enough to check the first one. + */ + preallocated = s->l1_size > 0 && s->l1_table[0] != 0; + if (qemu_in_coroutine()) { + qemu_co_mutex_unlock(&s->lock); + } + + if (!preallocated) { + return 1; + } else if (bs->encrypted) { + return 0; + } else { + return bdrv_has_zero_init(s->data_file->bs); + } +} + static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) { @@ -5187,7 +5214,7 @@ BlockDriver bdrv_qcow2 = { .bdrv_child_perm = bdrv_format_default_perms, .bdrv_co_create_opts = qcow2_co_create_opts, .bdrv_co_create = qcow2_co_create, - .bdrv_has_zero_init = bdrv_has_zero_init_1, + .bdrv_has_zero_init = qcow2_has_zero_init, .bdrv_has_zero_init_truncate = bdrv_has_zero_init_1, .bdrv_co_block_status = qcow2_co_block_status, |