[PATCH] staging: erofs: harden inode lookup for 32-bit platforms

[Gao Xiang]

On 2018/10/11 16:44, Dan Carpenter wrote:
> On Tue, Oct 09, 2018 at 10:07:13PM +0800, Gao Xiang wrote:
>> This patch introduces inode hash function, test and set callbacks,
>> and iget5_locked to find the right inode for 32-bit platforms.
>>
> 
> The way I read this changelog, we're trying to deal with corrupt file
> systems?  Is that correct?  Presumably in the current code it could lead
> to a Oops or something?

No, this commit isn't trying to deal with corrupt file systems.
In EROFS, the nid is not continuous and it represents the inode offset
inode offset = nid * 32.
Therefore the nid is 64-bit both for 32-bit and 64-bit platforms. However,
i_ino is 'unsigned long', which means for 32-bit platforms, i_ino is not enough
to contain the nid.

Therefore, we should use iget5_locked for this case.

> 
> regards,
> dan carpenter
>