On Wed, Aug 30, 2017 at 04:54:00PM +0200, Christoph Hellwig wrote:
> But reject reflink + DAX file systems for now until the code to
> support reflinks on DAX is actually implemented.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/xfs/xfs_super.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 38aaacdbb8b3..92521032468e 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1634,7 +1634,9 @@ xfs_fs_fill_super(
> }
> if (xfs_sb_version_hasreflink(&mp->m_sb))
> xfs_alert(mp,
> - "DAX and reflink have not been tested together!");
> + "DAX and reflink can not be used together!");
> + error = -EINVAL;
> + goto out_filestream_unmount;
/This/ hunk seems fine, but...
> }
>
> if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
> @@ -1648,10 +1650,6 @@ xfs_fs_fill_super(
> "EXPERIMENTAL reverse mapping btree feature enabled. Use at your own risk!");
> }
>
> - if (xfs_sb_version_hasreflink(&mp->m_sb))
> - xfs_alert(mp,
> - "EXPERIMENTAL reflink feature enabled. Use at your own risk!");
> -
...I frankly would rather wait until we land and stabilize the incore
extent rework, because I'd rather not have the reflink story be: 1) we
declare reflink stable in 4.14; 2) immediately people start loading up
XFSes with sparse VM images that blow up on high order allocations and
then 3) we get a whole lot of complaints about it. Then in 4.15 we 4)
land the incore extent map only now we're dragging those same users
through the mud while /that/ stabilizes, with the result 5) that
everyone thinks we've gone off the deep end and doesn't trust us
anymore.
I wish that didn't also mean waiting another 6 months for something that
none of us /developers/ have seen in practice, especially since the
enterprise distros will have plenty of time to backport all this stuff
before their next big releases if it /does/ become a problem. It's fine
enough for me (and Christoph's customers, evidently) but is that enough?
<shrug> Not sure what to do about my own fear factor. :) Anyone want to
offer further comments? A quick git history trip says sparse inodes
took about 13 months to go from initial commit to EXPERIMENTAL removed?
--D
> error = xfs_mountfs(mp);
> if (error)
> goto out_filestream_unmount;
> --
> 2.11.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
