From: "Darrick J. Wong" <djwong@kernel.org>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 1/2] xfs: improve FSGROWFSRT precondition checking
Date: Tue, 13 Jul 2021 21:59:17 -0700 [thread overview]
Message-ID: <20210714045917.GE22402@magnolia> (raw)
In-Reply-To: <20210714005850.GT664593@dread.disaster.area>
On Wed, Jul 14, 2021 at 10:58:50AM +1000, Dave Chinner wrote:
> On Mon, Jul 12, 2021 at 03:07:25PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > Improve the checking at the start of a realtime grow operation so that
> > we avoid accidentally set a new extent size that is too large and avoid
> > adding an rt volume to a filesystem with rmap or reflink because we
> > don't support rt rmap or reflink yet.
> >
> > While we're at it, separate the checks so that we're only testing one
> > aspect at a time.
> >
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
> > fs/xfs/xfs_rtalloc.c | 20 ++++++++++++++++----
> > 1 file changed, 16 insertions(+), 4 deletions(-)
> >
> >
> > diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
> > index 4e7be6b4ca8e..8920bce4fb0a 100644
> > --- a/fs/xfs/xfs_rtalloc.c
> > +++ b/fs/xfs/xfs_rtalloc.c
> > @@ -928,11 +928,23 @@ xfs_growfs_rt(
> > */
> > if (!capable(CAP_SYS_ADMIN))
> > return -EPERM;
> > - if (mp->m_rtdev_targp == NULL || mp->m_rbmip == NULL ||
> > - (nrblocks = in->newblocks) <= sbp->sb_rblocks ||
> > - (sbp->sb_rblocks && (in->extsize != sbp->sb_rextsize)))
> > + if (mp->m_rtdev_targp == NULL || !mp->m_rbmip || !mp->m_rsumip)
> > return -EINVAL;
>
> Shouldn't this use XFS_IS_REALTIME_MOUNT() so it always fails if
> CONFIG_XFS_RT=n?
xfs_rtalloc.c isn't even linked into the binary if CONFIG_XFS_RT=n.
> i.e. if we have to check mp->m_rbmip and mp->m_rsumip to determine
> if this mount is realtime enabled, then doesn't
> XFS_IS_REALTIME_MOUNT() need to be fixed?
TBH I think technically we could actually drop the m_rbmip/m_rsumip
checks since the mount will fail if those files cannot be iget'd.
That said, given how poorly tested realtime is, I figured it doesn't
hurt to double-check for this infrequent operation.
>
> > - if ((error = xfs_sb_validate_fsb_count(sbp, nrblocks)))
> > + if (in->newblocks <= sbp->sb_rblocks)
> > + return -EINVAL;
> > + if (xfs_sb_version_hasrealtime(&mp->m_sb) &&
> > + in->extsize != sbp->sb_rextsize)
> > + return -EINVAL;
>
> xfs_sb_version_hasrealtime() checks "sbp->sb_rblocks > 0", it's not
> an actual version flag check. I think this makes much more sense
> being open coded rather than masquerading as a feature check....
Ok, I'll change it back.
>
> > + if (XFS_FSB_TO_B(mp, in->extsize) > XFS_MAX_RTEXTSIZE ||
> > + XFS_FSB_TO_B(mp, in->extsize) < XFS_MIN_RTEXTSIZE)
> > + return -EINVAL;
> > + if (xfs_sb_version_hasrmapbt(&mp->m_sb) ||
> > + xfs_sb_version_hasreflink(&mp->m_sb))
> > + return -EOPNOTSUPP;
> > +
> > + nrblocks = in->newblocks;
> > + error = xfs_sb_validate_fsb_count(sbp, nrblocks);
> > + if (error)
> > return error;
>
> Otherwise looks like a reasonable set of additional checks.
Cool! Thanks for the review.
--D
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com
next prev parent reply other threads:[~2021-07-14 4:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-12 22:07 [PATCHSET 0/2] xfs: small fixes to realtime growfs Darrick J. Wong
2021-07-12 22:07 ` [PATCH 1/2] xfs: improve FSGROWFSRT precondition checking Darrick J. Wong
2021-07-14 0:58 ` Dave Chinner
2021-07-14 4:59 ` Darrick J. Wong [this message]
2021-07-12 22:07 ` [PATCH 2/2] xfs: fix an integer overflow error in xfs_growfs_rt Darrick J. Wong
2021-07-14 1:12 ` Dave Chinner
2021-07-14 5:00 ` Darrick J. Wong
2021-07-14 21:25 [PATCHSET v2 0/2] xfs: small fixes to realtime growfs Darrick J. Wong
2021-07-14 21:25 ` [PATCH 1/2] xfs: improve FSGROWFSRT precondition checking Darrick J. Wong
2021-07-14 23:44 ` Dave Chinner
2021-07-15 6:03 ` Christoph Hellwig
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