On Mon, Apr 02, 2018 at 12:57:24PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> If one of the backup superblocks is found to differ seriously from
> superblock 0, write out a fresh copy from the in-core sb.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
.....
> +/* Repair the superblock. */
> +int
> +xfs_repair_superblock(
> + struct xfs_scrub_context *sc)
> +{
> + struct xfs_mount *mp = sc->mp;
> + struct xfs_buf *bp;
> + struct xfs_dsb *sbp;
> + xfs_agnumber_t agno;
> + int error;
> +
> + /* Don't try to repair AG 0's sb; let xfs_repair deal with it. */
> + agno = sc->sm->sm_agno;
> + if (agno == 0)
> + return -EOPNOTSUPP;
> +
> + error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
> + XFS_AG_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
> + XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
If we are just overwriting the superblock, then use
xfs_trans_get_buf() so we don't need to do IO here.
> + if (error)
> + return error;
> + bp->b_ops = &xfs_sb_buf_ops;
> +
> + /* Copy AG 0's superblock to this one. */
> + sbp = XFS_BUF_TO_SBP(bp);
> + memset(sbp, 0, mp->m_sb.sb_sectsize);
That's a bit nasty. struct xfs_dsb is not a sector size in length.
xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
> + xfs_sb_to_disk(sbp, &mp->m_sb);
> + sbp->sb_bad_features2 = sbp->sb_features2;
Why is sb_bad_features2 not correct when taken from the incore
superblock?
> + /* Write this to disk. */
> + xfs_trans_buf_set_type(sc->tp, bp, XFS_BLFT_SB_BUF);
> + xfs_trans_log_buf(sc->tp, bp, 0, mp->m_sb.sb_sectsize - 1);
And why log this rather than just write it straight to disk? We've
never logged secondary superblocks before, so why now?
> int xfs_repair_setup_btree_extent_collection(struct xfs_scrub_context *sc);
>
> /* Metadata repairers */
> +int xfs_repair_superblock(struct xfs_scrub_context *sc);
>
> #else
>
> @@ -106,6 +107,8 @@ xfs_repair_calc_ag_resblks(
> return 0;
> }
>
> +#define xfs_repair_superblock (NULL)
Static inline, returns -EOPNOTSUPP. Or, as I'm suspecting that
all the patches are goign to do this - have a generic
xfs_repair_notsupported() function and define the functions
to that.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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