[PATCH] repair: Repair directory block CRC mismatches

[Jan Kara <jack@xxxxxxx>]

It can happen that just CRC doesn't match for directory blocks. In that
case xfs_repair will just report the error but won't fix anything (as
further checking of the block doesn't reveal any problems). Make sure we
recompute and write out new CRC when we failed verification during
reading.

Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 repair/dir2.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/repair/dir2.c b/repair/dir2.c
index 14c1435f5077..a189c161e569 100644
--- a/repair/dir2.c
+++ b/repair/dir2.c
@@ -596,7 +596,13 @@ _("bad level %d in block %u for directory inode %" PRIu64 
"\n"),
                 */
                ASSERT(cursor->level[this_level].dirty == 0 ||
                        (cursor->level[this_level].dirty && !no_modify));
-
+               /*
+                * If block looks ok but CRC didn't match, make sure to
+                * recompute it.
+                */
+               if (!no_modify &&
+                   cursor->level[this_level].bp->b_error == EFSBADCRC)
+                       cursor->level[this_level].dirty = 1;
                if (cursor->level[this_level].dirty && !no_modify)
                        libxfs_writebuf(cursor->level[this_level].bp, 0);
                else
@@ -1621,6 +1627,9 @@ _("bad directory block magic # %#x in block %u for 
directory inode %" PRIu64 "\n
                blp = (xfs_dir2_leaf_entry_t *)btp;
        rval = process_dir2_data(mp, ino, dip, ino_discovery, dirname, parent,
                bp, dot, dotdot, mp->m_dirdatablk, (char *)blp, &dirty);
+       /* If block looks ok but CRC didn't match, make sure to recompute it. */
+       if (!rval && bp->b_error == EFSBADCRC)
+               dirty = 1;
        if (dirty && !no_modify) {
                *repair = 1;
                libxfs_writebuf(bp, 0);
@@ -1784,6 +1793,12 @@ _("bad sibling back pointer for block %u in directory 
inode %" PRIu64 "\n"),
                        }
                }
                current_hashval = greatest_hashval;
+               /*
+                * If block looks ok but CRC didn't match, make sure to
+                * recompute it.
+                */
+               if (!no_modify && bp->b_error == EFSBADCRC)
+                       buf_dirty = 1;
                ASSERT(buf_dirty == 0 || (buf_dirty && !no_modify));
                if (buf_dirty && !no_modify) {
                        *repair = 1;
@@ -1927,8 +1942,12 @@ _("bad directory block magic # %#x in block %" PRIu64 " 
for directory inode %" P
                i = process_dir2_data(mp, ino, dip, ino_discovery, dirname,
                        parent, bp, dot, dotdot, (xfs_dablk_t)dbno,
                        (char *)data + mp->m_dirblksize, &dirty);
-               if (i == 0)
+               if (i == 0) {
                        good++;
+                       /* Maybe just CRC is wrong. Make sure we correct it. */
+                       if (bp->b_error == EFSBADCRC)
+                               dirty = 1;
+               }
                if (dirty && !no_modify) {
                        *repair = 1;
                        libxfs_writebuf(bp, 0);
-- 
1.8.1.4