xfs: repair the AGI

Rebuild the AGI header items with some help from the rmapbt.

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

3 files changed, 220 insertions, 1 deletions

diff --git a/fs/xfs/scrub/agheader_repair.c b/fs/xfs/scrub/agheader_repair.c
index 9ce302360bbb..f7568a4b5fe5 100644
--- a/fs/xfs/scrub/agheader_repair.c
+++ b/fs/xfs/scrub/agheader_repair.c
@@ -714,3 +714,220 @@ err:
         xfs_bitmap_destroy(&agfl_extents);
         return error;
 }
+
+/* AGI */
+
+/*
+ * Offset within the xrep_find_ag_btree array for each btree type.  Avoid the
+ * XFS_BTNUM_ names here to avoid creating a sparse array.
+ */
+enum {
+        XREP_AGI_INOBT = 0,
+        XREP_AGI_FINOBT,
+        XREP_AGI_END,
+        XREP_AGI_MAX
+};
+
+/*
+ * Given the inode btree roots described by *fab, find the roots, check them
+ * for sanity, and pass the root data back out via *fab.
+ */
+STATIC int
+xrep_agi_find_btrees(
+        struct xfs_scrub                *sc,
+        struct xrep_find_ag_btree       *fab)
+{
+        struct xfs_buf                  *agf_bp;
+        struct xfs_mount                *mp = sc->mp;
+        int                             error;
+
+        /* Read the AGF. */
+        error = xfs_alloc_read_agf(mp, sc->tp, sc->sa.agno, 0, &agf_bp);
+        if (error)
+                return error;
+        if (!agf_bp)
+                return -ENOMEM;
+
+        /* Find the btree roots. */
+        error = xrep_find_ag_btree_roots(sc, agf_bp, fab, NULL);
+        if (error)
+                return error;
+
+        /* We must find the inobt root. */
+        if (!xrep_check_btree_root(sc, &fab[XREP_AGI_INOBT]))
+                return -EFSCORRUPTED;
+
+        /* We must find the finobt root if that feature is enabled. */
+        if (xfs_sb_version_hasfinobt(&mp->m_sb) &&
+            !xrep_check_btree_root(sc, &fab[XREP_AGI_FINOBT]))
+                return -EFSCORRUPTED;
+
+        return 0;
+}
+
+/*
+ * Reinitialize the AGI header, making an in-core copy of the old contents so
+ * that we know which in-core state needs to be reinitialized.
+ */
+STATIC void
+xrep_agi_init_header(
+        struct xfs_scrub        *sc,
+        struct xfs_buf          *agi_bp,
+        struct xfs_agi          *old_agi)
+{
+        struct xfs_agi          *agi = XFS_BUF_TO_AGI(agi_bp);
+        struct xfs_mount        *mp = sc->mp;
+
+        memcpy(old_agi, agi, sizeof(*old_agi));
+        memset(agi, 0, BBTOB(agi_bp->b_length));
+        agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
+        agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
+        agi->agi_seqno = cpu_to_be32(sc->sa.agno);
+        agi->agi_length = cpu_to_be32(xfs_ag_block_count(mp, sc->sa.agno));
+        agi->agi_newino = cpu_to_be32(NULLAGINO);
+        agi->agi_dirino = cpu_to_be32(NULLAGINO);
+        if (xfs_sb_version_hascrc(&mp->m_sb))
+                uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
+
+        /* We don't know how to fix the unlinked list yet. */
+        memcpy(&agi->agi_unlinked, &old_agi->agi_unlinked,
+                        sizeof(agi->agi_unlinked));
+
+        /* Mark the incore AGF data stale until we're done fixing things. */
+        ASSERT(sc->sa.pag->pagi_init);
+        sc->sa.pag->pagi_init = 0;
+}
+
+/* Set btree root information in an AGI. */
+STATIC void
+xrep_agi_set_roots(
+        struct xfs_scrub                *sc,
+        struct xfs_agi                  *agi,
+        struct xrep_find_ag_btree       *fab)
+{
+        agi->agi_root = cpu_to_be32(fab[XREP_AGI_INOBT].root);
+        agi->agi_level = cpu_to_be32(fab[XREP_AGI_INOBT].height);
+
+        if (xfs_sb_version_hasfinobt(&sc->mp->m_sb)) {
+                agi->agi_free_root = cpu_to_be32(fab[XREP_AGI_FINOBT].root);
+                agi->agi_free_level = cpu_to_be32(fab[XREP_AGI_FINOBT].height);
+        }
+}
+
+/* Update the AGI counters. */
+STATIC int
+xrep_agi_calc_from_btrees(
+        struct xfs_scrub        *sc,
+        struct xfs_buf          *agi_bp)
+{
+        struct xfs_btree_cur    *cur;
+        struct xfs_agi          *agi = XFS_BUF_TO_AGI(agi_bp);
+        struct xfs_mount        *mp = sc->mp;
+        xfs_agino_t             count;
+        xfs_agino_t             freecount;
+        int                     error;
+
+        cur = xfs_inobt_init_cursor(mp, sc->tp, agi_bp, sc->sa.agno,
+                        XFS_BTNUM_INO);
+        error = xfs_ialloc_count_inodes(cur, &count, &freecount);
+        if (error)
+                goto err;
+        xfs_btree_del_cursor(cur, error);
+
+        agi->agi_count = cpu_to_be32(count);
+        agi->agi_freecount = cpu_to_be32(freecount);
+        return 0;
+err:
+        xfs_btree_del_cursor(cur, error);
+        return error;
+}
+
+/* Trigger reinitialization of the in-core data. */
+STATIC int
+xrep_agi_commit_new(
+        struct xfs_scrub        *sc,
+        struct xfs_buf          *agi_bp)
+{
+        struct xfs_perag        *pag;
+        struct xfs_agi          *agi = XFS_BUF_TO_AGI(agi_bp);
+
+        /* Trigger inode count recalculation */
+        xfs_force_summary_recalc(sc->mp);
+
+        /* Write this to disk. */
+        xfs_trans_buf_set_type(sc->tp, agi_bp, XFS_BLFT_AGI_BUF);
+        xfs_trans_log_buf(sc->tp, agi_bp, 0, BBTOB(agi_bp->b_length) - 1);
+
+        /* Now reinitialize the in-core counters if necessary. */
+        pag = sc->sa.pag;
+        pag->pagi_count = be32_to_cpu(agi->agi_count);
+        pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
+        pag->pagi_init = 1;
+
+        return 0;
+}
+
+/* Repair the AGI. */
+int
+xrep_agi(
+        struct xfs_scrub                *sc)
+{
+        struct xrep_find_ag_btree       fab[XREP_AGI_MAX] = {
+                [XREP_AGI_INOBT] = {
+                        .rmap_owner = XFS_RMAP_OWN_INOBT,
+                        .buf_ops = &xfs_inobt_buf_ops,
+                        .magic = XFS_IBT_CRC_MAGIC,
+                },
+                [XREP_AGI_FINOBT] = {
+                        .rmap_owner = XFS_RMAP_OWN_INOBT,
+                        .buf_ops = &xfs_inobt_buf_ops,
+                        .magic = XFS_FIBT_CRC_MAGIC,
+                },
+                [XREP_AGI_END] = {
+                        .buf_ops = NULL
+                },
+        };
+        struct xfs_agi                  old_agi;
+        struct xfs_mount                *mp = sc->mp;
+        struct xfs_buf                  *agi_bp;
+        struct xfs_agi                  *agi;
+        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);
+        /*
+         * Make sure we have the AGI buffer, as scrub might have decided it
+         * was corrupt after xfs_ialloc_read_agi failed with -EFSCORRUPTED.
+         */
+        error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
+                        XFS_AG_DADDR(mp, sc->sa.agno, XFS_AGI_DADDR(mp)),
+                        XFS_FSS_TO_BB(mp, 1), 0, &agi_bp, NULL);
+        if (error)
+                return error;
+        agi_bp->b_ops = &xfs_agi_buf_ops;
+        agi = XFS_BUF_TO_AGI(agi_bp);
+
+        /* Find the AGI btree roots. */
+        error = xrep_agi_find_btrees(sc, fab);
+        if (error)
+                return error;
+
+        /* Start rewriting the header and implant the btrees we found. */
+        xrep_agi_init_header(sc, agi_bp, &old_agi);
+        xrep_agi_set_roots(sc, agi, fab);
+        error = xrep_agi_calc_from_btrees(sc, agi_bp);
+        if (error)
+                goto out_revert;
+
+        /* Reinitialize in-core state. */
+        return xrep_agi_commit_new(sc, agi_bp);
+
+out_revert:
+        /* Mark the incore AGI state stale and revert the AGI. */
+        sc->sa.pag->pagi_init = 0;
+        memcpy(agi, &old_agi, sizeof(old_agi));
+        return error;
+}
diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
index 1d283360b5ab..9de321eee4ab 100644
--- a/fs/xfs/scrub/repair.h
+++ b/fs/xfs/scrub/repair.h
@@ -60,6 +60,7 @@ int xrep_probe(struct xfs_scrub *sc);
 int xrep_superblock(struct xfs_scrub *sc);
 int xrep_agf(struct xfs_scrub *sc);
 int xrep_agfl(struct xfs_scrub *sc);
+int xrep_agi(struct xfs_scrub *sc);
 
 #else
 
@@ -85,6 +86,7 @@ xrep_calc_ag_resblks(
 #define xrep_superblock                 xrep_notsupported
 #define xrep_agf                        xrep_notsupported
 #define xrep_agfl                       xrep_notsupported
+#define xrep_agi                        xrep_notsupported
 
 #endif /* CONFIG_XFS_ONLINE_REPAIR */
 
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 2670f4cf62f4..4bfae1e61d30 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -226,7 +226,7 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
                 .type   = ST_PERAG,
                 .setup  = xchk_setup_fs,
                 .scrub  = xchk_agi,
-                .repair = xrep_notsupported,
+                .repair = xrep_agi,
         },
         [XFS_SCRUB_TYPE_BNOBT] = {      /* bnobt */
                 .type   = ST_PERAG,