xfs: ensure that all metadata and data blocks are not cow staging extents

Make sure that all filesystem metadata blocks and file data blocks are
not also marked as CoW staging extents.  The extra checking added here
was inspired by an actual VM host filesystem corruption incident due to
bugs in the CoW handling of 4.x kernels.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
index 87cb13a..1a84153 100644 (file)
--- a/fs/xfs/scrub/agheader.c
+++ b/fs/xfs/scrub/agheader.c
@@ -53,6 +53,7 @@ xchk_superblock_xref(
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_xref_is_not_shared(sc, agbno, 1);
+       xchk_xref_is_not_cow_staging(sc, agbno, 1);
 
        /* scrub teardown will take care of sc->sa for us */
 }
@@ -517,6 +518,7 @@ xchk_agf_xref(
        xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_agf_xref_btreeblks(sc);
        xchk_xref_is_not_shared(sc, agbno, 1);
+       xchk_xref_is_not_cow_staging(sc, agbno, 1);
        xchk_agf_xref_refcblks(sc);
 
        /* scrub teardown will take care of sc->sa for us */
@@ -644,6 +646,7 @@ xchk_agfl_block_xref(
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_AG);
        xchk_xref_is_not_shared(sc, agbno, 1);
+       xchk_xref_is_not_cow_staging(sc, agbno, 1);
 }
 
 /* Scrub an AGFL block. */
@@ -700,6 +703,7 @@ xchk_agfl_xref(
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_xref_is_not_shared(sc, agbno, 1);
+       xchk_xref_is_not_cow_staging(sc, agbno, 1);
 
        /*
         * Scrub teardown will take care of sc->sa for us.  Leave sc->sa
@@ -855,6 +859,7 @@ xchk_agi_xref(
        xchk_agi_xref_icounts(sc);
        xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_xref_is_not_shared(sc, agbno, 1);
+       xchk_xref_is_not_cow_staging(sc, agbno, 1);
        xchk_agi_xref_fiblocks(sc);
 
        /* scrub teardown will take care of sc->sa for us */

diff --git a/fs/xfs/scrub/alloc.c b/fs/xfs/scrub/alloc.c
index 5920fe0..12dd55a 100644 (file)
--- a/fs/xfs/scrub/alloc.c
+++ b/fs/xfs/scrub/alloc.c
@@ -90,6 +90,7 @@ xchk_allocbt_xref(
        xchk_xref_is_not_inode_chunk(sc, agbno, len);
        xchk_xref_has_no_owner(sc, agbno, len);
        xchk_xref_is_not_shared(sc, agbno, len);
+       xchk_xref_is_not_cow_staging(sc, agbno, len);
 }
 
 /* Scrub a bnobt/cntbt record. */

diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
index 6188eba..be2c4da 100644 (file)
--- a/fs/xfs/scrub/bmap.c
+++ b/fs/xfs/scrub/bmap.c
@@ -328,12 +328,17 @@ xchk_bmap_iextent_xref(
        xchk_bmap_xref_rmap(info, irec, agbno);
        switch (info->whichfork) {
        case XFS_DATA_FORK:
-               if (xfs_is_reflink_inode(info->sc->ip))
-                       break;
-               fallthrough;
+               if (!xfs_is_reflink_inode(info->sc->ip))
+                       xchk_xref_is_not_shared(info->sc, agbno,
+                                       irec->br_blockcount);
+               xchk_xref_is_not_cow_staging(info->sc, agbno,
+                               irec->br_blockcount);
+               break;
        case XFS_ATTR_FORK:
                xchk_xref_is_not_shared(info->sc, agbno,
                                irec->br_blockcount);
+               xchk_xref_is_not_cow_staging(info->sc, agbno,
+                               irec->br_blockcount);
                break;
        case XFS_COW_FORK:
                xchk_xref_is_cow_staging(info->sc, agbno,

diff --git a/fs/xfs/scrub/ialloc.c b/fs/xfs/scrub/ialloc.c
index ca5a7e0..6d08613 100644 (file)
--- a/fs/xfs/scrub/ialloc.c
+++ b/fs/xfs/scrub/ialloc.c
@@ -115,7 +115,7 @@ xchk_iallocbt_chunk(
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 
        xchk_iallocbt_chunk_xref(bs->sc, irec, agino, bno, len);
-
+       xchk_xref_is_not_cow_staging(bs->sc, bno, len);
        return true;
 }
 

diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c
index bbf9432..50ebd72 100644 (file)
--- a/fs/xfs/scrub/inode.c
+++ b/fs/xfs/scrub/inode.c
@@ -558,6 +558,7 @@ xchk_inode_xref(
        xchk_inode_xref_finobt(sc, ino);
        xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_INODES);
        xchk_xref_is_not_shared(sc, agbno, 1);
+       xchk_xref_is_not_cow_staging(sc, agbno, 1);
        xchk_inode_xref_bmap(sc, dip);
 
 out_free:

diff --git a/fs/xfs/scrub/refcount.c b/fs/xfs/scrub/refcount.c
index 771a591..db9e46a 100644 (file)
--- a/fs/xfs/scrub/refcount.c
+++ b/fs/xfs/scrub/refcount.c
@@ -555,3 +555,24 @@ xchk_xref_is_not_shared(
        if (outcome != XBTREE_RECPACKING_EMPTY)
                xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
 }
+
+/* xref check that the extent is not being used for CoW staging. */
+void
+xchk_xref_is_not_cow_staging(
+       struct xfs_scrub        *sc,
+       xfs_agblock_t           agbno,
+       xfs_extlen_t            len)
+{
+       enum xbtree_recpacking  outcome;
+       int                     error;
+
+       if (!sc->sa.refc_cur || xchk_skip_xref(sc->sm))
+               return;
+
+       error = xfs_refcount_has_records(sc->sa.refc_cur, XFS_REFC_DOMAIN_COW,
+                       agbno, len, &outcome);
+       if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur))
+               return;
+       if (outcome != XBTREE_RECPACKING_EMPTY)
+               xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
+}

diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index d85c3b8..b6f452e 100644 (file)
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -172,6 +172,8 @@ void xchk_xref_is_cow_staging(struct xfs_scrub *sc, xfs_agblock_t bno,
                xfs_extlen_t len);
 void xchk_xref_is_not_shared(struct xfs_scrub *sc, xfs_agblock_t bno,
                xfs_extlen_t len);
+void xchk_xref_is_not_cow_staging(struct xfs_scrub *sc, xfs_agblock_t bno,
+               xfs_extlen_t len);
 #ifdef CONFIG_XFS_RT
 void xchk_xref_is_used_rt_space(struct xfs_scrub *sc, xfs_rtblock_t rtbno,
                xfs_extlen_t len);