xfs: repair the AGFL

Repair the AGFL from the rmap data.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

1 files changed, 281 insertions, 0 deletions

diff --git a/fs/xfs/scrub/agheader_repair.c b/fs/xfs/scrub/agheader_repair.c
index aa180492a4a5..9ce302360bbb 100644
--- a/fs/xfs/scrub/agheader_repair.c
+++ b/fs/xfs/scrub/agheader_repair.c
@@ -433,3 +433,284 @@ out_revert:
 	memcpy(agf, &old_agf, sizeof(old_agf));
 	return error;
 }
+
+/* AGFL */
+
+struct xrep_agfl {
+	/* Bitmap of other OWN_AG metadata blocks. */
+	struct xfs_bitmap	agmetablocks;
+
+	/* Bitmap of free space. */
+	struct xfs_bitmap	*freesp;
+
+	struct xfs_scrub	*sc;
+};
+
+/* Record all OWN_AG (free space btree) information from the rmap data. */
+STATIC int
+xrep_agfl_walk_rmap(
+	struct xfs_btree_cur	*cur,
+	struct xfs_rmap_irec	*rec,
+	void			*priv)
+{
+	struct xrep_agfl	*ra = priv;
+	xfs_fsblock_t		fsb;
+	int			error = 0;
+
+	if (xchk_should_terminate(ra->sc, &error))
+		return error;
+
+	/* Record all the OWN_AG blocks. */
+	if (rec->rm_owner == XFS_RMAP_OWN_AG) {
+		fsb = XFS_AGB_TO_FSB(cur->bc_mp, cur->bc_private.a.agno,
+				rec->rm_startblock);
+		error = xfs_bitmap_set(ra->freesp, fsb, rec->rm_blockcount);
+		if (error)
+			return error;
+	}
+
+	return xfs_bitmap_set_btcur_path(&ra->agmetablocks, cur);
+}
+
+/*
+ * Map out all the non-AGFL OWN_AG space in this AG so that we can deduce
+ * which blocks belong to the AGFL.
+ *
+ * Compute the set of old AGFL blocks by subtracting from the list of OWN_AG
+ * blocks the list of blocks owned by all other OWN_AG metadata (bnobt, cntbt,
+ * rmapbt).  These are the old AGFL blocks, so return that list and the number
+ * of blocks we're actually going to put back on the AGFL.
+ */
+STATIC int
+xrep_agfl_collect_blocks(
+	struct xfs_scrub	*sc,
+	struct xfs_buf		*agf_bp,
+	struct xfs_bitmap	*agfl_extents,
+	xfs_agblock_t		*flcount)
+{
+	struct xrep_agfl	ra;
+	struct xfs_mount	*mp = sc->mp;
+	struct xfs_btree_cur	*cur;
+	struct xfs_bitmap_range	*br;
+	struct xfs_bitmap_range	*n;
+	int			error;
+
+	ra.sc = sc;
+	ra.freesp = agfl_extents;
+	xfs_bitmap_init(&ra.agmetablocks);
+
+	/* Find all space used by the free space btrees & rmapbt. */
+	cur = xfs_rmapbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno);
+	error = xfs_rmap_query_all(cur, xrep_agfl_walk_rmap, &ra);
+	if (error)
+		goto err;
+	xfs_btree_del_cursor(cur, error);
+
+	/* Find all blocks currently being used by the bnobt. */
+	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
+			XFS_BTNUM_BNO);
+	error = xfs_bitmap_set_btblocks(&ra.agmetablocks, cur);
+	if (error)
+		goto err;
+	xfs_btree_del_cursor(cur, error);
+
+	/* Find all blocks currently being used by the cntbt. */
+	cur = xfs_allocbt_init_cursor(mp, sc->tp, agf_bp, sc->sa.agno,
+			XFS_BTNUM_CNT);
+	error = xfs_bitmap_set_btblocks(&ra.agmetablocks, cur);
+	if (error)
+		goto err;
+
+	xfs_btree_del_cursor(cur, error);
+
+	/*
+	 * Drop the freesp meta blocks that are in use by btrees.
+	 * The remaining blocks /should/ be AGFL blocks.
+	 */
+	error = xfs_bitmap_disunion(agfl_extents, &ra.agmetablocks);
+	xfs_bitmap_destroy(&ra.agmetablocks);
+	if (error)
+		return error;
+
+	/*
+	 * Calculate the new AGFL size.  If we found more blocks than fit in
+	 * the AGFL we'll free them later.
+	 */
+	*flcount = 0;
+	for_each_xfs_bitmap_extent(br, n, agfl_extents) {
+		*flcount += br->len;
+		if (*flcount > xfs_agfl_size(mp))
+			break;
+	}
+	if (*flcount > xfs_agfl_size(mp))
+		*flcount = xfs_agfl_size(mp);
+	return 0;
+
+err:
+	xfs_bitmap_destroy(&ra.agmetablocks);
+	xfs_btree_del_cursor(cur, error);
+	return error;
+}
+
+/* Update the AGF and reset the in-core state. */
+STATIC void
+xrep_agfl_update_agf(
+	struct xfs_scrub	*sc,
+	struct xfs_buf		*agf_bp,
+	xfs_agblock_t		flcount)
+{
+	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agf_bp);
+
+	ASSERT(flcount <= xfs_agfl_size(sc->mp));
+
+	/* Trigger fdblocks recalculation */
+	xfs_force_summary_recalc(sc->mp);
+
+	/* Update the AGF counters. */
+	if (sc->sa.pag->pagf_init)
+		sc->sa.pag->pagf_flcount = flcount;
+	agf->agf_flfirst = cpu_to_be32(0);
+	agf->agf_flcount = cpu_to_be32(flcount);
+	agf->agf_fllast = cpu_to_be32(flcount - 1);
+
+	xfs_alloc_log_agf(sc->tp, agf_bp,
+			XFS_AGF_FLFIRST | XFS_AGF_FLLAST | XFS_AGF_FLCOUNT);
+}
+
+/* Write out a totally new AGFL. */
+STATIC void
+xrep_agfl_init_header(
+	struct xfs_scrub	*sc,
+	struct xfs_buf		*agfl_bp,
+	struct xfs_bitmap	*agfl_extents,
+	xfs_agblock_t		flcount)
+{
+	struct xfs_mount	*mp = sc->mp;
+	__be32			*agfl_bno;
+	struct xfs_bitmap_range	*br;
+	struct xfs_bitmap_range	*n;
+	struct xfs_agfl		*agfl;
+	xfs_agblock_t		agbno;
+	unsigned int		fl_off;
+
+	ASSERT(flcount <= xfs_agfl_size(mp));
+
+	/*
+	 * Start rewriting the header by setting the bno[] array to
+	 * NULLAGBLOCK, then setting AGFL header fields.
+	 */
+	agfl = XFS_BUF_TO_AGFL(agfl_bp);
+	memset(agfl, 0xFF, BBTOB(agfl_bp->b_length));
+	agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
+	agfl->agfl_seqno = cpu_to_be32(sc->sa.agno);
+	uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
+
+	/*
+	 * Fill the AGFL with the remaining blocks.  If agfl_extents has more
+	 * blocks than fit in the AGFL, they will be freed in a subsequent
+	 * step.
+	 */
+	fl_off = 0;
+	agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agfl_bp);
+	for_each_xfs_bitmap_extent(br, n, agfl_extents) {
+		agbno = XFS_FSB_TO_AGBNO(mp, br->start);
+
+		trace_xrep_agfl_insert(mp, sc->sa.agno, agbno, br->len);
+
+		while (br->len > 0 && fl_off < flcount) {
+			agfl_bno[fl_off] = cpu_to_be32(agbno);
+			fl_off++;
+			agbno++;
+
+			/*
+			 * We've now used br->start by putting it in the AGFL,
+			 * so bump br so that we don't reap the block later.
+			 */
+			br->start++;
+			br->len--;
+		}
+
+		if (br->len)
+			break;
+		list_del(&br->list);
+		kmem_free(br);
+	}
+
+	/* Write new AGFL to disk. */
+	xfs_trans_buf_set_type(sc->tp, agfl_bp, XFS_BLFT_AGFL_BUF);
+	xfs_trans_log_buf(sc->tp, agfl_bp, 0, BBTOB(agfl_bp->b_length) - 1);
+}
+
+/* Repair the AGFL. */
+int
+xrep_agfl(
+	struct xfs_scrub	*sc)
+{
+	struct xfs_owner_info	oinfo;
+	struct xfs_bitmap	agfl_extents;
+	struct xfs_mount	*mp = sc->mp;
+	struct xfs_buf		*agf_bp;
+	struct xfs_buf		*agfl_bp;
+	xfs_agblock_t		flcount;
+	int			error;
+
+	/* We require the rmapbt to rebuild anything. */
+	if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
+		return -EOPNOTSUPP;
+
+	xchk_perag_get(sc->mp, &sc->sa);
+	xfs_bitmap_init(&agfl_extents);
+
+	/*
+	 * Read the AGF so that we can query the rmapbt.  We hope that there's
+	 * nothing wrong with the AGF, but all the AG header repair functions
+	 * have this chicken-and-egg problem.
+	 */
+	error = xfs_alloc_read_agf(mp, sc->tp, sc->sa.agno, 0, &agf_bp);
+	if (error)
+		return error;
+	if (!agf_bp)
+		return -ENOMEM;
+
+	/*
+	 * Make sure we have the AGFL buffer, as scrub might have decided it
+	 * was corrupt after xfs_alloc_read_agfl failed with -EFSCORRUPTED.
+	 */
+	error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
+			XFS_AG_DADDR(mp, sc->sa.agno, XFS_AGFL_DADDR(mp)),
+			XFS_FSS_TO_BB(mp, 1), 0, &agfl_bp, NULL);
+	if (error)
+		return error;
+	agfl_bp->b_ops = &xfs_agfl_buf_ops;
+
+	/* Gather all the extents we're going to put on the new AGFL. */
+	error = xrep_agfl_collect_blocks(sc, agf_bp, &agfl_extents, &flcount);
+	if (error)
+		goto err;
+
+	/*
+	 * Update AGF and AGFL.  We reset the global free block counter when
+	 * we adjust the AGF flcount (which can fail) so avoid updating any
+	 * buffers until we know that part works.
+	 */
+	xrep_agfl_update_agf(sc, agf_bp, flcount);
+	xrep_agfl_init_header(sc, agfl_bp, &agfl_extents, flcount);
+
+	/*
+	 * Ok, the AGFL should be ready to go now.  Roll the transaction to
+	 * make the new AGFL permanent before we start using it to return
+	 * freespace overflow to the freespace btrees.
+	 */
+	sc->sa.agf_bp = agf_bp;
+	sc->sa.agfl_bp = agfl_bp;
+	error = xrep_roll_ag_trans(sc);
+	if (error)
+		goto err;
+
+	/* Dump any AGFL overflow. */
+	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_AG);
+	return xrep_reap_extents(sc, &agfl_extents, &oinfo, XFS_AG_RESV_AGFL);
+err:
+	xfs_bitmap_destroy(&agfl_extents);
+	return error;
+}