fuse: don't unhash root

The root inode is assumed to be always hashed.  Do not unhash the root
inode even if it is marked BAD.

Fixes: 5d069dbe ("fuse: fix bad inode")
Cc: <stable@vger.kernel.org> # v5.11
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/fuse_i.h

@@ -994,7 +994,6 @@ static inline bool fuse_stale_inode(const struct inode *inode, int generation,
 
 static inline void fuse_make_bad(struct inode *inode)
 {
-	remove_inode_hash(inode);
 	set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
 }
 

fs/fuse/inode.c

@@ -475,8 +475,11 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 	} else if (fuse_stale_inode(inode, generation, attr)) {
 		/* nodeid was reused, any I/O on the old inode should fail */
 		fuse_make_bad(inode);
-		iput(inode);
-		goto retry;
+		if (inode != d_inode(sb->s_root)) {
+			remove_inode_hash(inode);
+			iput(inode);
+			goto retry;
+		}
 	}
 	fi = get_fuse_inode(inode);
 	spin_lock(&fi->lock);