recommending reiserfs?
John Thompson
john at os2.dhs.org
Sat May 8 03:25:49 UTC 2004
On Fri, 07 May 2004 11:17:16 -0500
Randy Kelsoe <randykel at swbell.net> wrote:
> John Thompson wrote:
>
> >fsck.xfs exists only because linux automatically runs fsck against
> >all filesystems as part of the boot process. When fsck.xfs is run, it
> >simply returns a successful message back to fsck so the boot process
> >can continue. When the boot process subsequently mounts the xfs
> >filesystem, xfs_check is run to determine if the filesystem is
> >"dirty" and then the journal is played back and/or xfs_repair will be
> >called to do the actual fixing.
> I could be wrong, but I understand that on boot, the filesystems are
> checked for the 'dirty bit' being set. When the system is shutdown
> cleanly, the 'dirty bit' is cleared. Once booted, the bit is set, so
> if the machine crashes without cleanly unmounting the filesystem, the
> bit will still be set. If the bit is not set, fsck is never run
> (unless an fsck is forced), and the machine is happy. If the bit is
> set, THEN fsck is called.
What do you think checks for the "dirty" bit? That's right; "fsck." If
it find the dirty bit set, it calls the filesystem-appropriate utility
(eg "fsck.ext3" or whatever) to check and fix any problems. When fsck
finds the dirty bit set on an xfs filesystem, it calls "fsck.xfs" which
simply returns a "successful" signal back to fsck, which then moves on
to the next filesystem. When the xfs filesystem is eventually mounted and
finds itself dirty, then xfs_check/xfs_restore are used to fix things up.
I suspect this round-about way of doing things is a result of xfs' IRIX
history, which does things slightly differently than linux. Creating a
dummy fsck.xfs utility allows xfs to be more easily integrated into the
linux scheme of things.
--
-John (john at os2.dhs.org)
More information about the fedora-list
mailing list