From fed050f3452da070fa90fc1b02c2bc2219d687a7 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 11 Apr 2023 19:00:38 -0700 Subject: [PATCH] xfs: cross-reference rmap records with ag btrees Strengthen the rmap btree record checker a little more by comparing OWN_FS and OWN_LOG reverse mappings against the AG headers and internal logs, respectively. Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner --- fs/xfs/Makefile | 2 +- fs/xfs/scrub/bitmap.c | 22 +++++++ fs/xfs/scrub/bitmap.h | 21 +++++++ fs/xfs/scrub/rmap.c | 159 +++++++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 202 insertions(+), 2 deletions(-) diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile index ac9d03c..16e4eb4 100644 --- a/fs/xfs/Makefile +++ b/fs/xfs/Makefile @@ -148,6 +148,7 @@ xfs-y += $(addprefix scrub/, \ agheader.o \ alloc.o \ attr.o \ + bitmap.o \ bmap.o \ btree.o \ common.o \ @@ -172,7 +173,6 @@ xfs-$(CONFIG_XFS_QUOTA) += scrub/quota.o ifeq ($(CONFIG_XFS_ONLINE_REPAIR),y) xfs-y += $(addprefix scrub/, \ agheader_repair.o \ - bitmap.o \ repair.o \ ) endif diff --git a/fs/xfs/scrub/bitmap.c b/fs/xfs/scrub/bitmap.c index dc139f0..85e5bed 100644 --- a/fs/xfs/scrub/bitmap.c +++ b/fs/xfs/scrub/bitmap.c @@ -396,3 +396,25 @@ xbitmap_empty( { return bitmap->xb_root.rb_root.rb_node == NULL; } + +/* Is the start of the range set or clear? And for how long? */ +bool +xbitmap_test( + struct xbitmap *bitmap, + uint64_t start, + uint64_t *len) +{ + struct xbitmap_node *bn; + uint64_t last = start + *len - 1; + + bn = xbitmap_tree_iter_first(&bitmap->xb_root, start, last); + if (!bn) + return false; + if (bn->bn_start <= start) { + if (bn->bn_last < last) + *len = bn->bn_last - start + 1; + return true; + } + *len = bn->bn_start - start; + return false; +} diff --git a/fs/xfs/scrub/bitmap.h b/fs/xfs/scrub/bitmap.h index 972d544..55441fe 100644 --- a/fs/xfs/scrub/bitmap.h +++ b/fs/xfs/scrub/bitmap.h @@ -38,6 +38,7 @@ int xbitmap_walk_bits(struct xbitmap *bitmap, xbitmap_walk_bits_fn fn, void *priv); bool xbitmap_empty(struct xbitmap *bitmap); +bool xbitmap_test(struct xbitmap *bitmap, uint64_t start, uint64_t *len); /* Bitmaps, but for type-checked for xfs_agblock_t */ @@ -66,6 +67,26 @@ static inline int xagb_bitmap_set(struct xagb_bitmap *bitmap, return xbitmap_set(&bitmap->agbitmap, start, len); } +static inline bool +xagb_bitmap_test( + struct xagb_bitmap *bitmap, + xfs_agblock_t start, + xfs_extlen_t *len) +{ + uint64_t biglen = *len; + bool ret; + + ret = xbitmap_test(&bitmap->agbitmap, start, &biglen); + + if (start + biglen >= UINT_MAX) { + ASSERT(0); + biglen = UINT_MAX - start; + } + + *len = biglen; + return ret; +} + static inline int xagb_bitmap_disunion(struct xagb_bitmap *bitmap, struct xagb_bitmap *sub) { diff --git a/fs/xfs/scrub/rmap.c b/fs/xfs/scrub/rmap.c index 6d7e294..759349c 100644 --- a/fs/xfs/scrub/rmap.c +++ b/fs/xfs/scrub/rmap.c @@ -12,10 +12,12 @@ #include "xfs_btree.h" #include "xfs_rmap.h" #include "xfs_refcount.h" +#include "xfs_ag.h" +#include "xfs_bit.h" #include "scrub/scrub.h" #include "scrub/common.h" #include "scrub/btree.h" -#include "xfs_ag.h" +#include "scrub/bitmap.h" /* * Set us up to scrub reverse mapping btrees. @@ -45,6 +47,13 @@ struct xchk_rmap { * that could be one. */ struct xfs_rmap_irec prev_rec; + + /* Bitmaps containing all blocks for each type of AG metadata. */ + struct xagb_bitmap fs_owned; + struct xagb_bitmap log_owned; + + /* Did we complete the AG space metadata bitmaps? */ + bool bitmaps_complete; }; /* Cross-reference a rmap against the refcount btree. */ @@ -249,6 +258,68 @@ xchk_rmapbt_check_mergeable( memcpy(&cr->prev_rec, irec, sizeof(struct xfs_rmap_irec)); } +/* Compare an rmap for AG metadata against the metadata walk. */ +STATIC int +xchk_rmapbt_mark_bitmap( + struct xchk_btree *bs, + struct xchk_rmap *cr, + const struct xfs_rmap_irec *irec) +{ + struct xfs_scrub *sc = bs->sc; + struct xagb_bitmap *bmp = NULL; + xfs_extlen_t fsbcount = irec->rm_blockcount; + + /* + * Skip corrupt records. It is essential that we detect records in the + * btree that cannot overlap but do, flag those as CORRUPT, and skip + * the bitmap comparison to avoid generating false XCORRUPT reports. + */ + if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + return 0; + + /* + * If the AG metadata walk didn't complete, there's no point in + * comparing against partial results. + */ + if (!cr->bitmaps_complete) + return 0; + + switch (irec->rm_owner) { + case XFS_RMAP_OWN_FS: + bmp = &cr->fs_owned; + break; + case XFS_RMAP_OWN_LOG: + bmp = &cr->log_owned; + break; + } + + if (!bmp) + return 0; + + if (xagb_bitmap_test(bmp, irec->rm_startblock, &fsbcount)) { + /* + * The start of this reverse mapping corresponds to a set + * region in the bitmap. If the mapping covers more area than + * the set region, then it covers space that wasn't found by + * the AG metadata walk. + */ + if (fsbcount < irec->rm_blockcount) + xchk_btree_xref_set_corrupt(bs->sc, + bs->sc->sa.rmap_cur, 0); + } else { + /* + * The start of this reverse mapping does not correspond to a + * completely set region in the bitmap. The region wasn't + * fully set by walking the AG metadata, so this is a + * cross-referencing corruption. + */ + xchk_btree_xref_set_corrupt(bs->sc, bs->sc->sa.rmap_cur, 0); + } + + /* Unset the region so that we can detect missing rmap records. */ + return xagb_bitmap_clear(bmp, irec->rm_startblock, irec->rm_blockcount); +} + /* Scrub an rmapbt record. */ STATIC int xchk_rmapbt_rec( @@ -268,9 +339,80 @@ xchk_rmapbt_rec( xchk_rmapbt_check_mergeable(bs, cr, &irec); xchk_rmapbt_check_overlapping(bs, cr, &irec); xchk_rmapbt_xref(bs->sc, &irec); + + return xchk_rmapbt_mark_bitmap(bs, cr, &irec); +} + +/* + * Set up bitmaps mapping all the AG metadata to compare with the rmapbt + * records. + */ +STATIC int +xchk_rmapbt_walk_ag_metadata( + struct xfs_scrub *sc, + struct xchk_rmap *cr) +{ + struct xfs_mount *mp = sc->mp; + int error; + + /* OWN_FS: AG headers */ + error = xagb_bitmap_set(&cr->fs_owned, XFS_SB_BLOCK(mp), + XFS_AGFL_BLOCK(mp) - XFS_SB_BLOCK(mp) + 1); + if (error) + goto out; + + /* OWN_LOG: Internal log */ + if (xfs_ag_contains_log(mp, sc->sa.pag->pag_agno)) { + error = xagb_bitmap_set(&cr->log_owned, + XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart), + mp->m_sb.sb_logblocks); + if (error) + goto out; + } + +out: + /* + * If there's an error, set XFAIL and disable the bitmap + * cross-referencing checks, but proceed with the scrub anyway. + */ + if (error) + xchk_btree_xref_process_error(sc, sc->sa.rmap_cur, + sc->sa.rmap_cur->bc_nlevels - 1, &error); + else + cr->bitmaps_complete = true; return 0; } +/* + * Check for set regions in the bitmaps; if there are any, the rmap records do + * not describe all the AG metadata. + */ +STATIC void +xchk_rmapbt_check_bitmaps( + struct xfs_scrub *sc, + struct xchk_rmap *cr) +{ + struct xfs_btree_cur *cur = sc->sa.rmap_cur; + unsigned int level; + + if (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT | + XFS_SCRUB_OFLAG_XFAIL)) + return; + if (!cur) + return; + level = cur->bc_nlevels - 1; + + /* + * Any bitmap with bits still set indicates that the reverse mapping + * doesn't cover the entire primary structure. + */ + if (xagb_bitmap_hweight(&cr->fs_owned) != 0) + xchk_btree_xref_set_corrupt(sc, cur, level); + + if (xagb_bitmap_hweight(&cr->log_owned) != 0) + xchk_btree_xref_set_corrupt(sc, cur, level); +} + /* Scrub the rmap btree for some AG. */ int xchk_rmapbt( @@ -283,8 +425,23 @@ xchk_rmapbt( if (!cr) return -ENOMEM; + xagb_bitmap_init(&cr->fs_owned); + xagb_bitmap_init(&cr->log_owned); + + error = xchk_rmapbt_walk_ag_metadata(sc, cr); + if (error) + goto out; + error = xchk_btree(sc, sc->sa.rmap_cur, xchk_rmapbt_rec, &XFS_RMAP_OINFO_AG, cr); + if (error) + goto out; + + xchk_rmapbt_check_bitmaps(sc, cr); + +out: + xagb_bitmap_destroy(&cr->log_owned); + xagb_bitmap_destroy(&cr->fs_owned); kfree(cr); return error; } -- 2.7.4