repair: detect CRC errors in AG headers

repair doesn't currently detect verifier errors in AG header
blocks - apart from the primary superblock they are not detected.
They are, fortunately, corrected in the important cases (AGF, AGI
and AGFL) because these structures are rebuilt in phase 5, but if
you run xfs_repair in checking mode it won't report them as bad.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/repair/scan.c b/repair/scan.c
index 1744c323581e1c61efb234b53c3c62a943723d5d..dec84ed2416cec238b05d6e5ce92624b2a042ad5 100644 (file)
--- a/repair/scan.c
+++ b/repair/scan.c
@@ -1207,39 +1207,38 @@ scan_ag(
        void            *arg)
 {
        struct aghdr_cnts *agcnts = arg;
-       xfs_agf_t       *agf;
-       xfs_buf_t       *agfbuf;
+       struct xfs_agf  *agf;
+       struct xfs_buf  *agfbuf = NULL;
        int             agf_dirty = 0;
-       xfs_agi_t       *agi;
-       xfs_buf_t       *agibuf;
+       struct xfs_agi  *agi;
+       struct xfs_buf  *agibuf = NULL;
        int             agi_dirty = 0;
-       xfs_sb_t        *sb;
-       xfs_buf_t       *sbbuf;
+       struct xfs_sb   *sb = NULL;
+       struct xfs_buf  *sbbuf = NULL;
        int             sb_dirty = 0;
        int             status;
+       char            *objname = NULL;
 
-       sbbuf = libxfs_readbuf(mp->m_dev, XFS_AG_DADDR(mp, agno, XFS_SB_DADDR),
-                               XFS_FSS_TO_BB(mp, 1), 0, &xfs_sb_buf_ops);
-       if (!sbbuf)  {
-               do_error(_("can't get root superblock for ag %d\n"), agno);
-               return;
-       }
-       sb = (xfs_sb_t *)calloc(BBSIZE, 1);
+       sb = (struct xfs_sb *)calloc(BBSIZE, 1);
        if (!sb) {
                do_error(_("can't allocate memory for superblock\n"));
-               libxfs_putbuf(sbbuf);
                return;
        }
+
+       sbbuf = libxfs_readbuf(mp->m_dev, XFS_AG_DADDR(mp, agno, XFS_SB_DADDR),
+                               XFS_FSS_TO_BB(mp, 1), 0, &xfs_sb_buf_ops);
+       if (!sbbuf)  {
+               objname = _("root superblock");
+               goto out_free_sb;
+       }
        libxfs_sb_from_disk(sb, XFS_BUF_TO_SBP(sbbuf));
 
        agfbuf = libxfs_readbuf(mp->m_dev,
                        XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
                        XFS_FSS_TO_BB(mp, 1), 0, &xfs_agf_buf_ops);
        if (!agfbuf)  {
-               do_error(_("can't read agf block for ag %d\n"), agno);
-               libxfs_putbuf(sbbuf);
-               free(sb);
-               return;
+               objname = _("agf block");
+               goto out_free_sbbuf;
        }
        agf = XFS_BUF_TO_AGF(agfbuf);
 
@@ -1247,11 +1246,8 @@ scan_ag(
                        XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
                        XFS_FSS_TO_BB(mp, 1), 0, &xfs_agi_buf_ops);
        if (!agibuf)  {
-               do_error(_("can't read agi block for ag %d\n"), agno);
-               libxfs_putbuf(agfbuf);
-               libxfs_putbuf(sbbuf);
-               free(sb);
-               return;
+               objname = _("agi block");
+               goto out_free_agfbuf;
        }
        agi = XFS_BUF_TO_AGI(agibuf);
 
@@ -1295,15 +1291,9 @@ scan_ag(
        }
 
        if (status && no_modify)  {
-               libxfs_putbuf(agibuf);
-               libxfs_putbuf(agfbuf);
-               libxfs_putbuf(sbbuf);
-               free(sb);
-
                do_warn(_("bad uncorrected agheader %d, skipping ag...\n"),
                        agno);
-
-               return;
+               goto out_free_agibuf;
        }
 
        scan_freelist(agf, agcnts);
@@ -1312,21 +1302,34 @@ scan_ag(
        validate_agi(agi, agno, agcnts);
 
        ASSERT(agi_dirty == 0 || (agi_dirty && !no_modify));
+       ASSERT(agf_dirty == 0 || (agf_dirty && !no_modify));
+       ASSERT(sb_dirty == 0 || (sb_dirty && !no_modify));
+
+       /*
+        * Only pay attention to CRC/verifier errors if we can correct them.
+        * While there, ensure that we corrected a corruption error if the
+        * verifier detected one.
+        */
+       if (!no_modify) {
+               ASSERT(agi_dirty || agibuf->b_error != EFSCORRUPTED);
+               ASSERT(agf_dirty || agfbuf->b_error != EFSCORRUPTED);
+               ASSERT(sb_dirty || sbbuf->b_error != EFSCORRUPTED);
+
+               agi_dirty += (agibuf->b_error == EFSBADCRC);
+               agf_dirty += (agfbuf->b_error == EFSBADCRC);
+               sb_dirty += (sbbuf->b_error == EFSBADCRC);
+       }
 
        if (agi_dirty && !no_modify)
                libxfs_writebuf(agibuf, 0);
        else
                libxfs_putbuf(agibuf);
 
-       ASSERT(agf_dirty == 0 || (agf_dirty && !no_modify));
-
        if (agf_dirty && !no_modify)
                libxfs_writebuf(agfbuf, 0);
        else
                libxfs_putbuf(agfbuf);
 
-       ASSERT(sb_dirty == 0 || (sb_dirty && !no_modify));
-
        if (sb_dirty && !no_modify) {
                if (agno == 0)
                        memcpy(&mp->m_sb, sb, sizeof(xfs_sb_t));
@@ -1341,6 +1344,18 @@ scan_ag(
        print_inode_list(i);
 #endif
        return;
+
+out_free_agibuf:
+       libxfs_putbuf(agibuf);
+out_free_agfbuf:
+       libxfs_putbuf(agfbuf);
+out_free_sbbuf:
+       libxfs_putbuf(sbbuf);
+out_free_sb:
+       free(sb);
+
+       if (objname)
+               do_error(_("can't get %s for ag %d\n"), objname, agno);
 }
 
 #define SCAN_THREADS 32