[PATCH v2 31/31] ocfs2: check extent list dinodes in online filecheck

[Joseph Qi]

Wire the extent list guard and its three sub-checks into the filecheck
validator: a zero l_count, an l_count beyond ocfs2_extent_recs_per_inode(),
and an l_next_free_rec beyond l_count.

This brings the filecheck validator to parity with
ocfs2_validate_inode_block() for every dinode check except the inline
xattr one.  ocfs2_validate_inode_xattr() calls ocfs2_error() through its
helpers in xattr.c, so sharing it would mean threading a reporting flag
down into that file; it is deliberately left out.

The l_next_free_rec predicate is already used by the repair path, which
fixes that field, so a repair of it now revalidates cleanly.

Signed-off-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
---
 fs/ocfs2/inode.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index ff46daf02509..ea2e2d2589d7 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -2204,6 +2204,37 @@ static int ocfs2_filecheck_validate_inode_block(struct super_block *sb,
 		goto bail;
 	}
 
+	if (ocfs2_dinode_has_extents(di)) {
+		struct ocfs2_extent_list *el = &di->id2.i_list;
+		u16 count = le16_to_cpu(el->l_count);
+		u16 next_free = le16_to_cpu(el->l_next_free_rec);
+
+		if (ocfs2_dinode_has_zero_extent_count(di)) {
+			mlog(ML_ERROR,
+			     "Filecheck: invalid dinode #%llu: extent list l_count is zero\n",
+			     (unsigned long long)bh->b_blocknr);
+			rc = -OCFS2_FILECHECK_ERR_INVALIDINO;
+			goto bail;
+		}
+
+		if (ocfs2_dinode_has_oversized_extent_count(sb, di)) {
+			mlog(ML_ERROR,
+			     "Filecheck: invalid dinode #%llu: extent list l_count %u exceeds max %u\n",
+			     (unsigned long long)bh->b_blocknr, count,
+			     ocfs2_extent_recs_per_inode(sb));
+			rc = -OCFS2_FILECHECK_ERR_INVALIDINO;
+			goto bail;
+		}
+
+		if (ocfs2_dinode_has_bad_extent_next_free(di)) {
+			mlog(ML_ERROR,
+			     "Filecheck: invalid dinode #%llu: extent list l_next_free_rec %u exceeds l_count %u\n",
+			     (unsigned long long)bh->b_blocknr, next_free, count);
+			rc = -OCFS2_FILECHECK_ERR_INVALIDINO;
+			goto bail;
+		}
+	}
+
 bail:
 	return rc;
 }
-- 
2.39.3