Re: [PATCH 8/8] block: drop unallocated_blocks_are_zero

2020-05-07 Thread Vladimir Sementsov-Ogievskiy
06.05.2020 18:14, Eric Blake wrote: On 5/6/20 4:25 AM, Vladimir Sementsov-Ogievskiy wrote: Currently this field only set by qed and qcow2. Well, only after patches 1-6 (prior to then, it was also set in protocol drivers).  I think you might be able to hoist part of this patch earlier in the

Re: [PATCH 8/8] block: drop unallocated_blocks_are_zero

2020-05-07 Thread Vladimir Sementsov-Ogievskiy
07.05.2020 10:05, Vladimir Sementsov-Ogievskiy wrote: 06.05.2020 18:14, Eric Blake wrote: On 5/6/20 4:25 AM, Vladimir Sementsov-Ogievskiy wrote: Currently this field only set by qed and qcow2. Well, only after patches 1-6 (prior to then, it was also set in protocol drivers).  I think you mig

Re: [PATCH 8/8] block: drop unallocated_blocks_are_zero

2020-05-07 Thread Vladimir Sementsov-Ogievskiy
06.05.2020 18:14, Eric Blake wrote: On 5/6/20 4:25 AM, Vladimir Sementsov-Ogievskiy wrote: Currently this field only set by qed and qcow2. Well, only after patches 1-6 (prior to then, it was also set in protocol drivers).  I think you might be able to hoist part of this patch earlier in the

Re: [PATCH 8/8] block: drop unallocated_blocks_are_zero

2020-05-06 Thread Eric Blake
On 5/6/20 4:25 AM, Vladimir Sementsov-Ogievskiy wrote: Currently this field only set by qed and qcow2. But in fact, all backing-supporting formats (parallels, qcow, qcow2, qed, vmdk) share this semantics: on unallocated blocks, if there is no backing file they just memset the buffer with zeroes.

Re: [PATCH 8/8] block: drop unallocated_blocks_are_zero

2020-05-06 Thread Vladimir Sementsov-Ogievskiy
06.05.2020 18:14, Eric Blake wrote: On 5/6/20 4:25 AM, Vladimir Sementsov-Ogievskiy wrote: Currently this field only set by qed and qcow2. Well, only after patches 1-6 (prior to then, it was also set in protocol drivers).  I think you might be able to hoist part of this patch earlier in the

Re: [PATCH 8/8] block: drop unallocated_blocks_are_zero

2020-05-06 Thread Eric Blake
On 5/6/20 4:25 AM, Vladimir Sementsov-Ogievskiy wrote: Currently this field only set by qed and qcow2. Well, only after patches 1-6 (prior to then, it was also set in protocol drivers). I think you might be able to hoist part of this patch earlier in the series, to make the changes to the pr

[PATCH 8/8] block: drop unallocated_blocks_are_zero

2020-05-06 Thread Vladimir Sementsov-Ogievskiy
Currently this field only set by qed and qcow2. But in fact, all backing-supporting formats (parallels, qcow, qcow2, qed, vmdk) share this semantics: on unallocated blocks, if there is no backing file they just memset the buffer with zeroes. So, document this behavior for .supports_backing and dro