On 1/22/21 3:46 PM, Omar Sandoval wrote:

From: Omar Sandoval <redacted>

This series adds an API for reading compressed data on a filesystem
without decompressing it as well as support for writing compressed data
directly to the filesystem. As with the previous submissions, I've
included a man page patch describing the API. I have test cases
(including fsstress support) and example programs which I'll send up
[1].

The main use-case is Btrfs send/receive: currently, when sending data
from one compressed filesystem to another, the sending side decompresses
the data and the receiving side recompresses it before writing it out.
This is wasteful and can be avoided if we can just send and write
compressed extents. The patches implementing the send/receive support
will be sent shortly.

Patches 1-3 add the VFS support and UAPI. Patch 4 is a fix that this
series depends on; it can be merged independently. Patches 5-8 are Btrfs
prep patches. Patch 9 adds Btrfs encoded read support and patch 10 adds
Btrfs encoded write support.

These patches are based on Dave Sterba's Btrfs misc-next branch [2],
which is in turn currently based on v5.11-rc4.

Is everybody OK with this?  Al?  I would like to go ahead and get this merged 
for the next merge window as long as everybody is OK with it, as it's blocking a 
fair bit of BTRFS work.  Thanks,

Josef