* Idea on compatibility for old distributions
@ 2016-05-10 1:16 Qu Wenruo
2016-05-10 1:52 ` Mark Fasheh
2016-05-10 20:23 ` Eric Sandeen
0 siblings, 2 replies; 6+ messages in thread
From: Qu Wenruo @ 2016-05-10 1:16 UTC (permalink / raw)
To: David Sterba, Mark Fasheh; +Cc: btrfs
Hi David, Mark,
In the recent test for new btrfs-convert backward compatibility, I found
that cmds-fi-du.c uses FIEMAP_EXTENT_SHARED bits, which is not present
in kernel of old distributions like RHEL6 (Sorry, didn't test on
openSUSE equivalent).
Unlike e2fsprogs, we can check its version with pkgconfig, any idea to
avoid such compiling error?
And further more, without kernel support for FIEMAP_EXTENT_SHARED, will
fi-du work anymore?
Thanks,
Qu
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Idea on compatibility for old distributions
2016-05-10 1:16 Idea on compatibility for old distributions Qu Wenruo
@ 2016-05-10 1:52 ` Mark Fasheh
2016-05-10 2:04 ` Qu Wenruo
2016-05-10 20:23 ` Eric Sandeen
1 sibling, 1 reply; 6+ messages in thread
From: Mark Fasheh @ 2016-05-10 1:52 UTC (permalink / raw)
To: Qu Wenruo; +Cc: David Sterba, btrfs
On Tue, May 10, 2016 at 09:16:04AM +0800, Qu Wenruo wrote:
> In the recent test for new btrfs-convert backward compatibility, I
> found that cmds-fi-du.c uses FIEMAP_EXTENT_SHARED bits, which is not
> present in kernel of old distributions like RHEL6 (Sorry, didn't
> test on openSUSE equivalent).
>
> Unlike e2fsprogs, we can check its version with pkgconfig, any idea
> to avoid such compiling error?
#ifndef FIEMAP_EXTENT_SHARED
#define FIEMAP_EXTENT_SHARED 0x00002000
#endif
This is what I do in duperemove. Many distributions dind't update their
kernel header packages for that bit so even though it's in the kernel
userspace programs using it won't compile.
> And further more, without kernel support for FIEMAP_EXTENT_SHARED,
> will fi-du work anymore?
RHEL6 says they're using 2.6.32 which is just before the introduction of
SHARED. It couild be that they have it though considering there is an
immense number of backports done for distro kernels. I would honestly check
the source. What we're really looking to see is what version of btrfs they
have.
With the above patch we would compile and run everywhere. If someone runs an
obsolete version of btrfs then fi du won't report any shared extents. This
is unfortunate but so is running btrfs from 2.6.32.
--Mark
--
Mark Fasheh
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Idea on compatibility for old distributions
2016-05-10 1:52 ` Mark Fasheh
@ 2016-05-10 2:04 ` Qu Wenruo
0 siblings, 0 replies; 6+ messages in thread
From: Qu Wenruo @ 2016-05-10 2:04 UTC (permalink / raw)
To: Mark Fasheh; +Cc: David Sterba, btrfs
Mark Fasheh wrote on 2016/05/09 18:52 -0700:
> On Tue, May 10, 2016 at 09:16:04AM +0800, Qu Wenruo wrote:
>> In the recent test for new btrfs-convert backward compatibility, I
>> found that cmds-fi-du.c uses FIEMAP_EXTENT_SHARED bits, which is not
>> present in kernel of old distributions like RHEL6 (Sorry, didn't
>> test on openSUSE equivalent).
>>
>> Unlike e2fsprogs, we can check its version with pkgconfig, any idea
>> to avoid such compiling error?
>
> #ifndef FIEMAP_EXTENT_SHARED
> #define FIEMAP_EXTENT_SHARED 0x00002000
> #endif
>
> This is what I do in duperemove. Many distributions dind't update their
> kernel header packages for that bit so even though it's in the kernel
> userspace programs using it won't compile.
Oh, I just forgot such easy fix. :)
>
>
>> And further more, without kernel support for FIEMAP_EXTENT_SHARED,
>> will fi-du work anymore?
>
> RHEL6 says they're using 2.6.32 which is just before the introduction of
> SHARED. It couild be that they have it though considering there is an
> immense number of backports done for distro kernels. I would honestly check
> the source. What we're really looking to see is what version of btrfs they
> have.
>
> With the above patch we would compile and run everywhere. If someone runs an
> obsolete version of btrfs then fi du won't report any shared extents. This
> is unfortunate but so is running btrfs from 2.6.32.
> --Mark
As long as compile passes, it's completely acceptable.
Hopes the patch will be sent out soon.
Thanks,
Qu
>
> --
> Mark Fasheh
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Idea on compatibility for old distributions
2016-05-10 1:16 Idea on compatibility for old distributions Qu Wenruo
2016-05-10 1:52 ` Mark Fasheh
@ 2016-05-10 20:23 ` Eric Sandeen
[not found] ` <15f7b634-f173-d73f-5c17-8d9294f1efd7@cn.fujitsu.com>
1 sibling, 1 reply; 6+ messages in thread
From: Eric Sandeen @ 2016-05-10 20:23 UTC (permalink / raw)
To: Qu Wenruo, David Sterba, Mark Fasheh; +Cc: btrfs
On 5/9/16 8:16 PM, Qu Wenruo wrote:
> Hi David, Mark,
>
> In the recent test for new btrfs-convert backward compatibility, I
> found that cmds-fi-du.c uses FIEMAP_EXTENT_SHARED bits, which is not
> present in kernel of old distributions like RHEL6 (Sorry, didn't test
> on openSUSE equivalent).
There is really no need to invest in compatibility with such old
distros IMHO. As Phoronix breathlessly points out today, the tech preview
of btrfs in RHEL6 has ended, and it is now deprecated in RHEL6.
RHEL6-era btrfs was an interesting experiment, but it is one that will
not continue.
Thanks,
-Eric
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-05-12 9:22 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-05-10 1:16 Idea on compatibility for old distributions Qu Wenruo
2016-05-10 1:52 ` Mark Fasheh
2016-05-10 2:04 ` Qu Wenruo
2016-05-10 20:23 ` Eric Sandeen
[not found] ` <15f7b634-f173-d73f-5c17-8d9294f1efd7@cn.fujitsu.com>
[not found] ` <20160512083755.GJ29353@suse.cz>
2016-05-12 8:51 ` Qu Wenruo
2016-05-12 9:22 ` David Sterba
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