Archipelago » qemu

vpc: Implement .bdrv_has_zero_init

Depending on the subformat, has_zero_init on VHD must behave like raw
and query the underlying storage (fixed) or like other sparse formats
that can always return 1 (dynamic, differencing).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/ssh: Set bdrv_has_zero_init according to the file type.

If the remote is a regular file, set it to true (ie. reads of
uninitialized areas in a newly created file will return zeroes).
If we can't prove that, return false (a safe default).

Tested by adding a debugging print statement [not part of this commit]...

vmdk: remove wrong calculation of relative path

When creating image with backing file, the driver tries to calculate the
relative path from created image file to backing file, but the path
computation is incorrect. e.g.:

$ qemu-img create -f vmdk -b vmdk-data-disk.vmdk vmdk-data-snapshot1...

block: add basic backup support to block driver

backup_start() creates a block job that copies a point-in-time snapshot
of a block device to a target block device.

We call backup_do_cow() for each write during backup. That function
reads the original data from the block device before it gets...

qcow2: Batch discards

This optimises the discard operation for freed clusters by batching
discard requests (both snapshot deletion and bdrv_discard end up
updating the refcounts cluster by cluster).

Note that we don't discard asynchronously, but keep s->lock held. This...