[linux-lvm] Re: LVM 2.2 snapshot bug

Andrea Arcangeli andrea at suse.de
Wed Nov 8 16:31:13 UTC 2000

On Wed, Nov 08, 2000 at 12:04:50AM +0100, Rik van Riel wrote:
> I haven't checked yet if LVM actually returns an error
> to ext3 or if it just silently (well, except for the

After ll_rw_block(WRITE) returns the buffer will be clean and _not_ uptodate.
That's the only way a blockdevice reports I/O errors to highlevel layers.

> Exposing a read-only device as read-write to the users
> will cause a bit of confusion, yes :)

I agree.

> Though I guess Stephen's decision to do log replay on
> read-only mounted filesystems on read-write block
> devices is certainly a defendable decision. Btw, don't

Yes, I'm not complaining that decsion.

What I am saying is that the major bug here is that ext3 Oopses the kernel when
it gets I/O errors because of faulty harddisk during recovery, not that LVM
forgot to set the ro_bits just like the floppy disk when it's read only and
the floppy disk case is likely to be unfixable infact. I can't see any
bug in LVM that could explain an Oops.

>the reiserfs people do the same?

About reiserfs I don't know what it does but I guess it does the same.

Chris, could you try to mount reiserfs in readonly mode on a snapshot
blockdevice and see what happens?


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