[PATCH 22/30] ocfs2: check dinode nlink and mode in online filecheck

[Joseph Qi]

The filecheck validator shares most of its conditions with
ocfs2_validate_inode_block(), but skips the zero nlink or mode check.
Wire it in using the predicate the two now share.

Filecheck reports OCFS2_FILECHECK_ERR_INVALIDINO and logs with the
Filecheck prefix rather than calling ocfs2_error(), which would escalate
to ocfs2_handle_error() and could force the filesystem read-only while
an administrator is only asking for a diagnosis.

The check is placed after the ecc and signature gate so that the
existing coupling is preserved: a bad signature still overrides a
checksum failure with INVALIDINO, and every later check still runs only
on an ecc-clean block.

Signed-off-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
---
 fs/ocfs2/inode.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index cfa545981310..07b9445bb538 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -2009,6 +2009,15 @@ static int ocfs2_filecheck_validate_inode_block(struct super_block *sb,
 		goto bail;
 	}
 
+	if (ocfs2_dinode_has_zero_nlink_or_mode(di)) {
+		mlog(ML_ERROR,
+		     "Filecheck: invalid dinode #%llu: nlink = %u or mode = %u\n",
+		     (unsigned long long)bh->b_blocknr,
+		     ocfs2_read_links_count(di), le16_to_cpu(di->i_mode));
+		rc = -OCFS2_FILECHECK_ERR_INVALIDINO;
+		goto bail;
+	}
+
 	if (!ocfs2_valid_inode_mode(le16_to_cpu(di->i_mode))) {
 		mlog(ML_ERROR,
 		     "Filecheck: invalid dinode #%llu: mode 0%o has unknown file type\n",
-- 
2.39.3