[PATCH 0/2] btrfs: remove the tailing zeros from compressed inline extents

[Qu Wenruo <wqu@suse.com>]

Commit 3eaf5f082c4c ("btrfs: extract inlined creation into a dedicated
delalloc helper") changed the compression input from [0, i_size) to [0,
blocksize), which caused two problems:

- Other tools unable to decompress the inlined extent

  U-boot and btrfs-restore are affected, as they only allocated a buffer
  which is @ram_bytes sized.
  That buffer is too small to contain the decompressed data, which is
  @sectorsize.

  Those projects are fixed to have a more robust decompression routine
  which can handle both cases now.

- Worse ratio for those compressed inline extent.

  For the same 3K 0xcd filled range, the results are small but
  observable, 48 vs 61 bytes.

Filipe's v1 fix is very close to a proper fix, but btrfs will unable to
create inlined extents for lzo.
It turns out to be another bug in the copy_compressed_data_to_bio()
function.

So this series is to properly fix the bug, firstly fix the lzo
regression which prevents inlined extent creation, then we can apply
Filipe's v1 fix.

However since Filipe's v3 is already in the for-next, the second patch
is reverting part of the v3 fix while keeping the extra size check, then
apply v1 fix.

If the series got reviewed, I'll change the 2nd patch to use Filipe's v1
fix with extra checks from v3 kept.

Qu Wenruo (2):
  btrfs: fix the incorrect lzo space saving checks
  btrfs: remove the trailing zeros from compressed inline extent

 fs/btrfs/inode.c |  7 +------
 fs/btrfs/lzo.c   | 32 +++++++++++++++++++++++++-------
 2 files changed, 26 insertions(+), 13 deletions(-)

-- 
2.55.0