udf: Skip parent dir link count update if corrupted

[ Upstream commit c5566903af56dd1abb092f18dcb0c770d6cd8dcb ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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)));