Hi Filipe, Chris,
I did more profiling work, and I want to writeup some of the things I
noticed. Hopefully it has some value for the community.
# btrfs_transaction.dirty_pages:
This "extent_io_tree" includes every eb created by
btrfs_init_new_buffer (this is the only function that adds dirty
exte
On Mon, Jul 13, 2015 at 06:55:29PM +0200, Alex Lyakas wrote:
> Filipe,
> Thanks for the explanation. Those reasons were not so obvious for me.
>
> Would it make sense not to COW the block in case-1, if we are mounted
> with "notreelog"? Or, perhaps, to check that the block does not belong
> to a l
Filipe,
Thanks for the explanation. Those reasons were not so obvious for me.
Would it make sense not to COW the block in case-1, if we are mounted
with "notreelog"? Or, perhaps, to check that the block does not belong
to a log tree?
The second case is more difficult. One problem is that
BTRFS_HE
On Sun, Jul 12, 2015 at 6:15 PM, Alex Lyakas wrote:
> Greetings,
> Looking at the code of should_cow_block(), I see:
>
> if (btrfs_header_generation(buf) == trans->transid &&
>!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
> ...
> So if the extent buffer has been written to disk, and no
Greetings,
Looking at the code of should_cow_block(), I see:
if (btrfs_header_generation(buf) == trans->transid &&
!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
...
So if the extent buffer has been written to disk, and now is changed again
in the same transaction, we insist on COW'ing
