On 12.08.19 17:33, Vladimir Sementsov-Ogievskiy wrote: > 25.07.2019 18:55, Max Reitz wrote: >> vpc is not really a passthrough driver, even when using the fixed >> subformat (where host and guest offsets are equal). It should handle >> preallocation like all other drivers do, namely by returning >> DATA | RECURSE instead of RAW. >> >> There is no tangible difference but the fact that bdrv_is_allocated() no >> longer falls through to the protocol layer. > > Hmm. Isn't a real bug (fixed by this patch) ? > > Assume vpc->file is qcow2 with backing, which have "unallocated" region, > which is > backed by actual data in backing file.
Come on now. > So, this region will be reported as not allocated and will be skipped by any > copying > loop using block-status? Is it a bug of BDRV_BLOCK_RAW itself? Or I don't > understand > something.. I think what you don’t understand is that if you have a vpc file inside of a qcow2 file, you’re doing basically everything wrong. ;-) But maybe we should drop BDRV_BLOCK_RAW... Does it do anything good for us in the raw driver? Shouldn’t it too just return DATA | RECURSE? Max
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