[PATCH 12/27] xfs: scrub AGF and AGFL

Darrick J. Wong
2017-09-21T00:18:53Z

Check the block references in the AGF and AGFL headers to make sure
they make sense.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_fs.h | 4 +
fs/xfs/scrub/agheader.c | 220 +++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/common.c | 60 +++++++++++++
fs/xfs/scrub/common.h | 6 +
fs/xfs/scrub/scrub.c | 8 ++
fs/xfs/scrub/scrub.h | 2
6 files changed, 299 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index b98bba2..a22d90f 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -485,9 +485,11 @@ struct xfs_scrub_metadata {
/* Scrub subcommands. */
#define XFS_SCRUB_TYPE_TEST 0 /* presence test ioctl */
#define XFS_SCRUB_TYPE_SB 1 /* superblock */
+#define XFS_SCRUB_TYPE_AGF 2 /* AG free header */
+#define XFS_SCRUB_TYPE_AGFL 3 /* AG free list */

/* Number of scrub subcommands. */
-#define XFS_SCRUB_TYPE_NR 2
+#define XFS_SCRUB_TYPE_NR 4

/* i: Repair this metadata. */
#define XFS_SCRUB_IFLAG_REPAIR (1 << 0)
diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
index c58a5ef..c2cc2af 100644
--- a/fs/xfs/scrub/agheader.c
+++ b/fs/xfs/scrub/agheader.c
@@ -49,6 +49,72 @@ xfs_scrub_setup_ag_header(
return xfs_scrub_setup_fs(sc, ip);
}

+/* Find the size of the AG, in blocks. */
+static inline xfs_agblock_t
+xfs_scrub_ag_blocks(
+ struct xfs_mount *mp,
+ xfs_agnumber_t agno)
+{
+ ASSERT(agno < mp->m_sb.sb_agcount);
+
+ if (agno < mp->m_sb.sb_agcount - 1)
+ return mp->m_sb.sb_agblocks;
+ return mp->m_sb.sb_dblocks - (agno * mp->m_sb.sb_agblocks);
+}
+
+/* Walk all the blocks in the AGFL. */
+int
+xfs_scrub_walk_agfl(
+ struct xfs_scrub_context *sc,
+ int (*fn)(struct xfs_scrub_context *,
+ xfs_agblock_t bno, void *),
+ void *priv)
+{
+ struct xfs_agf *agf;
+ __be32 *agfl_bno;
+ struct xfs_mount *mp = sc->mp;
+ unsigned int flfirst;
+ unsigned int fllast;
+ int i;
+ int error;
+
+ agf = XFS_BUF_TO_AGF(sc->sa.agf_bp);
+ agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, sc->sa.agfl_bp);
+ flfirst = be32_to_cpu(agf->agf_flfirst);
+ fllast = be32_to_cpu(agf->agf_fllast);
+
+ /* Skip an empty AGFL. */
+ if (agf->agf_flcount == cpu_to_be32(0))
+ return 0;
+
+ /* first to last is a consecutive list. */
+ if (fllast >= flfirst) {
+ for (i = flfirst; i <= fllast; i++) {
+ error = fn(sc, be32_to_cpu(agfl_bno[i]), priv);
+ if (error)
+ return error;
+ }
+
+ return 0;
+ }
+
+ /* first to the end */
+ for (i = flfirst; i < XFS_AGFL_SIZE(mp); i++) {
+ error = fn(sc, be32_to_cpu(agfl_bno[i]), priv);
+ if (error)
+ return error;
+ }
+
+ /* the start to last. */
+ for (i = 0; i <= fllast; i++) {
+ error = fn(sc, be32_to_cpu(agfl_bno[i]), priv);
+ if (error)
+ return error;
+ }
+
+ return 0;
+}
+
/* Superblock */

/* Scrub the filesystem superblock. */
@@ -324,3 +390,157 @@ xfs_scrub_superblock(

return error;
}
+
+/* AGF */
+
+/* Scrub the AGF. */
+int
+xfs_scrub_agf(
+ struct xfs_scrub_context *sc)
+{
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_agf *agf;
+ xfs_daddr_t daddr;
+ xfs_daddr_t eofs;
+ xfs_agnumber_t agno;
+ xfs_agblock_t agbno;
+ xfs_agblock_t eoag;
+ xfs_agblock_t agfl_first;
+ xfs_agblock_t agfl_last;
+ xfs_agblock_t agfl_count;
+ xfs_agblock_t fl_count;
+ int level;
+ int error = 0;
+
+ agno = sc->sm->sm_agno;
+ error = xfs_scrub_load_ag_headers(sc, agno, XFS_SCRUB_TYPE_AGF);
+ if (!xfs_scrub_op_ok(sc, agno, XFS_AGF_BLOCK(sc->mp), &error))
+ goto out;
+
+ agf = XFS_BUF_TO_AGF(sc->sa.agf_bp);
+ eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
+
+ /* Check the AG length */
+ eoag = be32_to_cpu(agf->agf_length);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ eoag == xfs_scrub_ag_blocks(mp, agno));
+
+ /* Check the AGF btree roots and levels */
+ agbno = be32_to_cpu(agf->agf_roots[XFS_BTNUM_BNO]);
+ daddr = XFS_AGB_TO_DADDR(mp, agno, agbno);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ agbno > XFS_AGI_BLOCK(mp) &&
+ agbno < mp->m_sb.sb_agblocks &&
+ agbno < eoag && daddr < eofs);
+
+ agbno = be32_to_cpu(agf->agf_roots[XFS_BTNUM_CNT]);
+ daddr = XFS_AGB_TO_DADDR(mp, agno, agbno);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ agbno > XFS_AGI_BLOCK(mp) &&
+ agbno < mp->m_sb.sb_agblocks &&
+ agbno < eoag && daddr < eofs);
+
+ level = be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ level > 0 && level <= XFS_BTREE_MAXLEVELS);
+
+ level = be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ level > 0 && level <= XFS_BTREE_MAXLEVELS);
+
+ if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+ agbno = be32_to_cpu(agf->agf_roots[XFS_BTNUM_RMAP]);
+ daddr = XFS_AGB_TO_DADDR(mp, agno, agbno);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ agbno > XFS_AGI_BLOCK(mp) &&
+ agbno < mp->m_sb.sb_agblocks &&
+ agbno < eoag && daddr < eofs);
+
+ level = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ level > 0 && level <= XFS_BTREE_MAXLEVELS);
+ }
+
+ if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+ agbno = be32_to_cpu(agf->agf_refcount_root);
+ daddr = XFS_AGB_TO_DADDR(mp, agno, agbno);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ agbno > XFS_AGI_BLOCK(mp) &&
+ agbno < mp->m_sb.sb_agblocks &&
+ agbno < eoag && daddr < eofs);
+
+ level = be32_to_cpu(agf->agf_refcount_level);
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ level > 0 && level <= XFS_BTREE_MAXLEVELS);
+ }
+
+ /* Check the AGFL counters */
+ agfl_first = be32_to_cpu(agf->agf_flfirst);
+ agfl_last = be32_to_cpu(agf->agf_fllast);
+ agfl_count = be32_to_cpu(agf->agf_flcount);
+ if (agfl_last > agfl_first)
+ fl_count = agfl_last - agfl_first + 1;
+ else
+ fl_count = XFS_AGFL_SIZE(mp) - agfl_first + agfl_last + 1;
+ xfs_scrub_block_check_ok(sc, sc->sa.agf_bp,
+ agfl_count == 0 || fl_count == agfl_count);
+
+out:
+ return error;
+}
+
+/* AGFL */
+
+struct xfs_scrub_agfl {
+ xfs_agblock_t eoag;
+ xfs_daddr_t eofs;
+};
+
+/* Scrub an AGFL block. */
+STATIC int
+xfs_scrub_agfl_block(
+ struct xfs_scrub_context *sc,
+ xfs_agblock_t agbno,
+ void *priv)
+{
+ struct xfs_mount *mp = sc->mp;
+ xfs_agnumber_t agno = sc->sa.agno;
+ struct xfs_scrub_agfl *sagfl = priv;
+ int error = 0;
+
+ xfs_scrub_block_check_ok(sc, sc->sa.agfl_bp,
+ agbno > XFS_AGI_BLOCK(mp) &&
+ agbno < mp->m_sb.sb_agblocks &&
+ agbno < sagfl->eoag &&
+ XFS_AGB_TO_DADDR(mp, agno, agbno) < sagfl->eofs);
+
+ return error;
+}
+
+/* Scrub the AGFL. */
+int
+xfs_scrub_agfl(
+ struct xfs_scrub_context *sc)
+{
+ struct xfs_scrub_agfl sagfl;
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_agf *agf;
+ xfs_agnumber_t agno;
+ int error;
+
+ agno = sc->sm->sm_agno;
+ error = xfs_scrub_load_ag_headers(sc, agno, XFS_SCRUB_TYPE_AGFL);
+ if (!xfs_scrub_op_ok(sc, agno, XFS_AGFL_BLOCK(sc->mp), &error))
+ goto out;
+ if (!sc->sa.agf_bp)
+ return -EFSCORRUPTED;
+
+ agf = XFS_BUF_TO_AGF(sc->sa.agf_bp);
+ sagfl.eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
+ sagfl.eoag = be32_to_cpu(agf->agf_length);
+
+ /* Check the blocks in the AGFL. */
+ return xfs_scrub_walk_agfl(sc, xfs_scrub_agfl_block, &sagfl);
+out:
+ return error;
+}
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index 1e80f23..e0e611d 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -463,6 +463,66 @@ xfs_scrub_ag_init(
return xfs_scrub_ag_btcur_init(sc, sa);
}

+/*
+ * Load and verify an AG header for further AG header examination.
+ * If this header is not the target of the examination, don't return
+ * the buffer if a runtime or verifier error occurs.
+ */
+STATIC int
+xfs_scrub_load_ag_header(
+ struct xfs_scrub_context *sc,
+ xfs_daddr_t daddr,
+ struct xfs_buf **bpp,
+ const struct xfs_buf_ops *ops,
+ bool is_target)
+{
+ struct xfs_mount *mp = sc->mp;
+ int error;
+
+ *bpp = NULL;
+ error = xfs_trans_read_buf(mp, sc->tp, mp->m_ddev_targp,
+ XFS_AG_DADDR(mp, sc->sa.agno, daddr),
+ XFS_FSS_TO_BB(mp, 1), 0, bpp, ops);
+ return is_target ? error : 0;
+}
+
+/*
+ * Load as many of the AG headers and btree cursors as we can for an
+ * examination and cross-reference of an AG header.
+ */
+int
+xfs_scrub_load_ag_headers(
+ struct xfs_scrub_context *sc,
+ xfs_agnumber_t agno,
+ unsigned int type)
+{
+ struct xfs_mount *mp = sc->mp;
+ int error;
+
+ ASSERT(type == XFS_SCRUB_TYPE_AGF || type == XFS_SCRUB_TYPE_AGFL);
+ memset(&sc->sa, 0, sizeof(sc->sa));
+ sc->sa.agno = agno;
+
+ error = xfs_scrub_load_ag_header(sc, XFS_AGI_DADDR(mp),
+ &sc->sa.agi_bp, &xfs_agi_buf_ops, false);
+ if (error)
+ return error;
+
+ error = xfs_scrub_load_ag_header(sc, XFS_AGF_DADDR(mp),
+ &sc->sa.agf_bp, &xfs_agf_buf_ops,
+ type == XFS_SCRUB_TYPE_AGF);
+ if (error)
+ return error;
+
+ error = xfs_scrub_load_ag_header(sc, XFS_AGFL_DADDR(mp),
+ &sc->sa.agfl_bp, &xfs_agfl_buf_ops,
+ type == XFS_SCRUB_TYPE_AGFL);
+ if (error)
+ return error;
+
+ return 0;
+}
+
/* Per-scrubber setup functions */

/* Set us up with a transaction and an empty context. */
diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h
index 4c7c308..4d9a56c 100644
--- a/fs/xfs/scrub/common.h
+++ b/fs/xfs/scrub/common.h
@@ -104,5 +104,11 @@ int xfs_scrub_ag_read_headers(struct xfs_scrub_context *sc, xfs_agnumber_t agno,
void xfs_scrub_ag_btcur_free(struct xfs_scrub_ag *sa);
int xfs_scrub_ag_btcur_init(struct xfs_scrub_context *sc,
struct xfs_scrub_ag *sa);
+int xfs_scrub_load_ag_headers(struct xfs_scrub_context *sc, xfs_agnumber_t agno,
+ unsigned int type);
+int xfs_scrub_walk_agfl(struct xfs_scrub_context *sc,
+ int (*fn)(struct xfs_scrub_context *, xfs_agblock_t bno,
+ void *),
+ void *priv);

#endif /* __XFS_SCRUB_COMMON_H__ */
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 8e08224..1afce7b 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -166,6 +166,14 @@ static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
.setup = xfs_scrub_setup_ag_header,
.scrub = xfs_scrub_superblock,
},
+ { /* agf */
+ .setup = xfs_scrub_setup_ag_header,
+ .scrub = xfs_scrub_agf,
+ },
+ { /* agfl */
+ .setup = xfs_scrub_setup_ag_header,
+ .scrub = xfs_scrub_agfl,
+ },
};

/* Dispatch metadata scrubbing. */
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index 027f62e..cb31a01 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -63,5 +63,7 @@ struct xfs_scrub_context {
/* Metadata scrubbers */
int xfs_scrub_tester(struct xfs_scrub_context *sc);
int xfs_scrub_superblock(struct xfs_scrub_context *sc);
+int xfs_scrub_agf(struct xfs_scrub_context *sc);
+int xfs_scrub_agfl(struct xfs_scrub_context *sc);

#endif /* __XFS_SCRUB_SCRUB_H__ */