Re: btrfs: compression breaks cp and cross-FS mv, FS_IOC_FIEMAP bug?

From: Marti Raudsepp
Date: Mon Feb 14 2011 - 12:59:18 EST


On Mon, Feb 14, 2011 at 17:01, Chris Mason <chris.mason@xxxxxxxxxx> wrote:
> Or, it could just be delalloc ;)

I suspect delalloc. After creating the file, filefrag reports "1
extent found", but for some reason it doesn't actually print out
details of the extent.

After a "sync" call, the extent appears and "cp" starts working as expected:

% rm -f foo bar
% echo foo > foo
% sync
% filefrag -v foo
Filesystem type is: 9123683e
File size of foo is 4 (1 block, blocksize 4096)
ext logical physical expected length flags
0 0 0 4096 not_aligned,inline,eof
foo: 1 extent found
% cp foo bar
% hexdump bar
0000000 6f66 0a6f
0000004

Without sync:

% rm -f foo bar
% echo foo > foo
% filefrag -v foo
Filesystem type is: 9123683e
File size of foo is 4 (1 block, blocksize 4096)
ext logical physical expected length flags
foo: 1 extent found
% cp foo bar
% hexdump bar
0000000 0000 0000
0000004

Regards,
Marti
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