On Wed, Jul 30, 2014 at 12:29:14PM -0400, Brian Foster wrote:
> On Wed, Jul 30, 2014 at 12:30:24PM +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@xxxxxxxxxx>
> >
> > We recently had a bug where buffers were slipping through log
> > recovery without any verifier attached to them. This was resulting
> > in on-disk CRC mismatches for valid data. Add some warning code to
> > catch this occurrence so that we catch such bugs during development
> > rather than not being aware they exist.
> >
> > Note that we cannot do this verification unconditionally as non-CRC
> > filesystems don't always attach verifiers to the buffers being
> > written. e.g. during log recovery we cannot identify all the
> > different types of buffers correctly on non-CRC filesystems, so we
> > can't attach the correct verifiers in all cases and so we don't
> > attach any. Hence we don't want on non-CRC filesystems to avoid
> > spamming the logs with false indications.
> >
> > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> > ---
> > fs/xfs/xfs_buf.c | 15 +++++++++++++++
> > fs/xfs/xfs_log.c | 7 ++++++-
> > 2 files changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> > index a6dc83e..078b8be 100644
> > --- a/fs/xfs/xfs_buf.c
> > +++ b/fs/xfs/xfs_buf.c
> > @@ -1330,6 +1330,21 @@ _xfs_buf_ioapply(
> > SHUTDOWN_CORRUPT_INCORE);
> > return;
> > }
> > + } else if (bp->b_bn != -1LL) {
> > + struct xfs_mount *mp = bp->b_target->bt_mount;
> > +
> > + /*
> > + * non-crc filesystems don't attach verifiers during
> > + * log recovery, so don't warn for such filesystems.
> > + */
> > + if (xfs_sb_version_hascrc(&mp->m_sb)) {
> > + xfs_warn(mp,
> > + "%s: no ops on block 0x%llx/0x%llx",
> > + __func__, bp->b_bn,
> > + bp->b_maps[0].bm_bn);
>
> Are you intending to print both block number values here or the
> b_bn/bm_len combo?
Yeah, I probably did. I didn't actuall look at the block numbers in
the output I kept getting - just the magic number in the hex dump
and the stack trace...
>
> > + xfs_hex_dump(bp->b_addr, 64);
> > + dump_stack();
> > + }
> > }
> > } else if (bp->b_flags & XBF_READ_AHEAD) {
> > rw = READA;
> > diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> > index 149a4a5..9dc92b3 100644
> > --- a/fs/xfs/xfs_log.c
> > +++ b/fs/xfs/xfs_log.c
> > @@ -1378,8 +1378,13 @@ xlog_alloc_log(
> >
> > xlog_get_iclog_buffer_size(mp, log);
> >
> > + /*
> > + * Use a block number of -1 for the extra log buffer used during splits
> > + * so that it will trigger errors if we ever try to do IO on it without
> > + * first having set it up properly.
> > + */
> > error = -ENOMEM;
> > - bp = xfs_buf_alloc(mp->m_logdev_targp, 0, BTOBB(log->l_iclog_size), 0);
> > + bp = xfs_buf_alloc(mp->m_logdev_targp, -1LL, BTOBB(log->l_iclog_size), 0);
>
> How about XFS_BUF_DADDR_NULL (here and above)?
Will fix.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
_______________________________________________
xfs mailing list
xfs@xxxxxxxxxxx
http://oss.sgi.com/mailman/listinfo/xfs
