Re: review: use correct buffer flags when reading superblock

David Chinner
2007-10-11T03:30:48Z

On Thu, Oct 11, 2007 at 12:42:25PM +1000, Lachlan McIlroy wrote:
> David Chinner wrote:
> >On Wed, Oct 10, 2007 at 06:37:47PM +1000, Lachlan McIlroy wrote:
> >>When reading the superblock during log recovery we are not setting
> >>the correct buffer flags. Specifically we are not turning off flags
> >>we do not need such as XBF_ASYNC that is causing the synchronous
> >>xfs_iowait() to hang. We should also turn off XBF_WRITE and remove
> >>the buffer from the delay write queue just to be safe.
> >
> >We really don't need the removal of the write flags - the XFS_bflush()
> >call above the xfs_getsb() call guarantees that they won't be set....
>
> It's not obvious though. It wasn't obvious that ASYNC was still set
> and look where that got us.

Sure, but it is incorrect to have them set at that point - incorrect
enough that it might cause corruption. That is, if they are set
then the changes made during log replay have not been written to
disk and we've got bigger problems than a hanging I/O to worry
about....

So rather than clearing them, we should be asserting that the
write flags are not set at all.

Cheers,

Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group