From: Dave Chinner <david@fromorbit.com>
To: Brian Foster <bfoster@redhat.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH v2] repair: use fs rootino for dummy parent value instead of zero
Date: Mon, 20 Jul 2020 13:21:43 +1000 [thread overview]
Message-ID: <20200720032143.GC2005@dread.disaster.area> (raw)
In-Reply-To: <20200717115920.59986-1-bfoster@redhat.com>
On Fri, Jul 17, 2020 at 07:59:20AM -0400, Brian Foster wrote:
> If a directory inode has an invalid parent ino on disk, repair
> replaces the invalid value with a dummy value of zero in the buffer
> and NULLFSINO in the in-core parent tracking. The zero value serves
> no functional purpose as it is still an invalid value and the parent
> must be repaired by phase 6 based on the in-core state before the
> buffer can be written out. A consequence of using an invalid dummy
> value is that phase 6 requires custom verifier infrastructure to
> detect the invalid parent inode and temporarily replace it while the
> core fork verifier runs. If we use a valid inode number as a dummy
> value earlier in repair, this workaround can be removed.
>
> An obvious choice for a valid dummy parent inode value is the
> orphanage inode. However, the orphanage inode is not allocated until
> much later in repair when the filesystem structure is established as
> sound and placement of orphaned inodes is imminent. In this case, it
> is too early to know for sure whether the associated inodes are
> orphaned because a directory traversal later in repair can locate
> references to the inode and repair the parent value based on the
> structure of the directory tree.
>
> Given all of this, escalate the preexisting workaround from the
> custom verifier in phase 6 and set the root inode value as a dummy
> parent for shortform directories with an invalid on-disk parent. The
> in-core parent is still tracked as NULLFSINO and so forces repair to
> either update the parent or orphan the inode before repair
> completes.
>
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>
> v2:
> - Update patch subject and commit log.
Looks good.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-07-20 3:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 14:08 [PATCH 0/4] xfsprogs: remove custom dir2 sf fork verifier from repair Brian Foster
2020-07-15 14:08 ` [PATCH 1/4] repair: set the in-core inode parent in phase 3 Brian Foster
2020-07-15 18:42 ` Christoph Hellwig
2020-07-21 0:57 ` Darrick J. Wong
2020-07-15 14:08 ` [PATCH 2/4] repair: don't double check dir2 sf parent in phase 4 Brian Foster
2020-07-15 18:43 ` Christoph Hellwig
2020-07-15 23:54 ` Darrick J. Wong
2020-07-16 10:39 ` Brian Foster
2020-07-21 0:55 ` Darrick J. Wong
2020-07-15 14:08 ` [PATCH 3/4] repair: use fs root ino for dummy parent value instead of zero Brian Foster
2020-07-15 18:44 ` Christoph Hellwig
2020-07-15 22:22 ` Dave Chinner
2020-07-16 10:41 ` Brian Foster
2020-07-16 22:06 ` Dave Chinner
2020-07-17 11:57 ` Brian Foster
2020-07-17 11:59 ` [PATCH v2] repair: use fs rootino " Brian Foster
2020-07-20 3:21 ` Dave Chinner [this message]
2020-07-21 0:47 ` Darrick J. Wong
2020-07-15 14:08 ` [PATCH 4/4] repair: remove custom dir2 sf fork verifier from phase6 Brian Foster
2020-07-15 18:44 ` Christoph Hellwig
2020-07-21 0:47 ` Darrick J. Wong
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