Messages in this thread |  | | | Date | Thu, 17 Jan 2008 00:38:38 -0700 | | From | Andreas Dilger <> | | Subject | Re: [Patch] document ext3 requirements (was Re: [RFD] Incremental fsck) |
On Jan 15, 2008 22:05 -0500, Rik van Riel wrote:
> With a filesystem that is compartmentalized and checksums metadata,
> I believe that an online fsck is absolutely worth having.
>
> Instead of the filesystem resorting to mounting the whole volume
> read-only on certain errors, part of the filesystem can be offlined
> while an fsck runs. This could even be done automatically in many
> situations.
In ext4 we store per-group state flags in each group, and the group
descriptor is checksummed (to detect spurious flags), so it should
be relatively straight forward to store an "error" flag in a single
group and have it become read-only.
As a starting point, it would be worthwhile to check instances of
ext4_error() to see how many of them can be targetted at a specific
group. I'd guess most of them could be (corrupt inodes, directory
and indirect blocks, incorrect bitmaps).
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
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