udf: Skip parent dir link count update if corrupted

If the parent directory link count is too low (likely directory inode
corruption), just skip updating its link count as if it goes to 0 too
early it can cause unexpected issues.

Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 78a603129dd583dd12170330df668a690f018590..2be775d30ac104e7c046237da21faa770f4adc6c 100644 (file)
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -517,7 +517,11 @@ static int udf_rmdir(struct inode *dir, struct dentry *dentry)
                         inode->i_nlink);
        clear_nlink(inode);
        inode->i_size = 0;
-       inode_dec_link_count(dir);
+       if (dir->i_nlink >= 3)
+               inode_dec_link_count(dir);
+       else
+               udf_warn(inode->i_sb, "parent dir link count too low (%u)\n",
+                        dir->i_nlink);
        udf_add_fid_counter(dir->i_sb, true, -1);
        inode_set_mtime_to_ts(dir,
                              inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));