Based on the provided code slice and the specified vulnerability types (CWE-416, CWE-476, CWE-787) among the given lines, the most likely vulnerability is CWE-476 (NULL Pointer Dereference) on line 29. The vulnerability occurs because there's no check to ensure that `inode` or `inode->i_mapping` is not NULL before dereferencing it.

Here are five possible patches to address this vulnerability:

Patch 1:
```c
6 	struct inode *inode = bdev->bd_inode;
7 	int err;
8 
9 	if (!inode || !inode->i_mapping)
10 		return -EINVAL;
11 
```

Patch 2:
```c
28 	if (!inode || !inode->i_mapping)
29 		return -EINVAL;
30 	filemap_invalidate_lock(inode->i_mapping);
```

Patch 3:
```c
28 	if (inode && inode->i_mapping) {
29 		filemap_invalidate_lock(inode->i_mapping);
30 		err = truncate_bdev_range(bdev, mode, start, start + len - 1);
31 		if (err)
32 			goto fail;
33 		err = blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
34 	fail:
35 		filemap_invalidate_unlock(inode->i_mapping);
36 	} else {
37 		err = -EINVAL;
38 	}
```

Patch 4:
```c
6 	struct inode *inode = bdev->bd_inode;
7 	struct address_space *mapping;
8 	int err;
9 
10 	if (!inode)
11 		return -EINVAL;
12 
13 	mapping = inode->i_mapping;
14 	if (!mapping)
15 		return -EINVAL;
```

Patch 5:
```c
28 	if (!inode) {
29 		return -EINVAL;
30 	}
31 	if (!inode->i_mapping) {
32 		return -EINVAL;
33 	}
34 	filemap_invalidate_lock(inode->i_mapping);
```

These patches add checks to ensure that `inode` and `inode->i_mapping` are not NULL before they are used, preventing potential NULL pointer dereferences.