drv_co_block_status digs bs->file for additional, more accurate search
for hole inside region, reported as DATA by bs since 5daa74a6eb.
This accuracy is not free: assume we have qcow2 disk. Actually, qcow2
knows, where are holes and where is data. But every block_status
request calls lseek additionally. Assume a big disk, full of
data, in any iterative copying block job (or img convert) we'll call
lseek(HOLE) on every iteration, and each of these lseeks will have to
iterate through all metadata up to the end of file. It's obviously
ineffective behavior. And for many scenarios we don't need this lseek
at all.
However, lseek is needed when we have metadata-preallocated image.
So, let's detect metadata-preallocation case and don't dig qcow2's
protocol file in other cases.
The idea is to compare allocation size in POV of filesystem with
allocations size in POV of Qcow2 (by refcounts). If allocation in fs is
significantly lower, consider it as metadata-preallocation case.
102 iotest changed, as our detector can't detect shrinked file as
metadata-preallocation, which don't seem to be wrong, as with metadata
preallocation we always have valid file length.
Two other iotests have a slight change in their QMP output sequence:
Active 'block-commit' returns earlier because the job coroutine yields
earlier on a blocking operation. This operation is loading the refcount
blocks in qcow2_detect_metadata_preallocation().
Suggested-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
102 truncates a qcow2 file (the raw file) on purpose while a VM is
running. However, image locking will usually prevent exactly this.
The fact that most people have not noticed until now (I suppose you may
have seen sporadic failures, but not taken them too seriously, like me)
further shows that this truncation is actually not really done
concurrently, but that the VM is still starting up by this point and has
not yet opened the image. Remedy this by waiting for the monitor shell
to appear before the qemu-img invocation so we know the VM is up.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171129185102.29390-1-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Mixing byte offset and sector allocation counts is a bit
confusing. Also, reporting n/m sectors, where m decreases
according to the remaining size of the file, isn't really
adding any useful information; and reporting an offset at
both the front and end of the line, with large amounts of
whitespace, is pointless. Update the output to use byte
counts and shorter lines, then adjust the affected tests
(./check -qcow2 102, ./check -vpc 146).
Note that 'qemu-io map' is MUCH weaker than 'qemu-img map';
the former only shows which regions of the active layer are
allocated, without regards to where the allocation comes from
or whether the allocated portion is known to read as zero
(because it is using the weaker bdrv_is_allocated()); while the
latter (especially in --output=json mode) reports more details
from bdrv_get_block_status().
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20170429191419.30051-4-eblake@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
It should not be happening, but it is possible to truncate an image
outside of qemu while qemu is running (or any of the qemu tools using
the block layer. raw_co_get_block_status() should not break then.
While touching this test, replace the existing "truncate" invocation by
"$QEMU_IMG convert -f raw".
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1414148280-17949-4-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Add a test for qemu-img map and qemu-io -c map on truncated files.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
