Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
/ 2006-09-28 16:23:46 +0200
\ Werner Fischer:
> On Thu, 2006-09-28 at 11:18 +0200, Lars Ellenberg wrote:
> > the reason it "works" here, and not for you is probably this,
> > from kernel ChangeLog-2.6.9:
> > <ecashin at coraid.com>
> > [PATCH] fix block layer ioctl bug
> >
> > If the blockdev doesn't implement BLKFLSBUF and returns -ENOTTY we should
> > still go ahead and perform the VFS-level sync. We need to test for both
> > ENOTTY and EINVAL because some SCSI drivers incorrectly return EINVAL.
> >
> > Signed-off-by: Ed L Cashin <ecashin at coraid.com>
> > Signed-off-by: Andrew Morton <akpm at osdl.org>
> > Signed-off-by: Linus Torvalds <torvalds at osdl.org>
> >
> > > On your side: what does DRBD upon "blockdev --flushbufs /dev/drbd0" -
> > > does DRBD forward the flush command to the lower devices?
> >
> > DRBD does nothing but return ENOTTY...
> > Maybe we want to put something in there, like you suggest.
> > but (for kernels including the patch mentioned above),
> > block/ioctl.c blkdev_ioctl() does the right thing, namely:
> > lock_kernel();
> > fsync_bdev(bdev);
> > invalidate_bdev(bdev, 0);
> > unlock_kernel();
> > return 0;
> >
> > so I think there is no hurry...
> I think you are right for kernels >= 2.6.9
>
> Do you see a problem in using DRBD in kernel 2.6.8 (without the patch
> mentioned above)?
>
> As far as I understand it, with kernel 2.6.8 (without the patch) this
> "VFS-level sync" is not done. Can this lead to any problems when I use
> DRBD?
you came from the heartbeat Filesystem resource script.
I'll cite it:
#
# Make sure the kernel does the right thing with the FS buffers
# This function should be called after unmounting and before mounting
# It may not be necessary in 2.4 and later kernels, but it shouldn't hurt
# anything either...
#
# It's really a bug that you have to do this at all...
#
flushbufs() {
...
so, since in kernels more recent than stone-age mount/umount does the
vfs-sync, it is ok to not do this explicitly in that resource script.
--
: Lars Ellenberg Tel +43-1-8178292-0 :
: LINBIT Information Technologies GmbH Fax +43-1-8178292-82 :
: Schoenbrunner Str. 244, A-1120 Vienna/Europe http://www.linbit.com :
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