[PATCH 5/5] xfs: use xfs_ialloc_blks_per_cluster in xfs_imap

[Jeff Liu]

On 12/12 2013 07:39 AM, Dave Chinner wrote:
> On Wed, Dec 11, 2013 at 09:48:35PM +0800, Jeff Liu wrote:
>> From: Jie Liu <jeff.liu at oracle.com>
>>
>> Use xfs_ialloc_blks_per_cluster() in xfs_imap().  Please note that we
>> previously calculate the number of blocks per cluster without taking
>> the situation of that the inode cluster size might be equal to or less
>> than the SB blocksize into account.  Maybe there is a chance to cause
>> potential issues after handling an untrusted inode number lookup and
>> proceed to check if the inode number maps to a block is outsides the
>> file system bounds or not.
> 
> I don't think there's any issues here - after all the inode lookups
> and mapping is done, the code in xfs_imap checks that the cluster
> that the inode is mapped to lies wholly within the filesystem
> boundaries. Hence I think you can remove that from the patch
> descritpion.
Ah, you're right because the current logic can handle it well if
blks_per_cluster > 1, or there is no influence to calculate the
cluster_agbno if blks_per_cluster == 1. :)

Thanks,
-Jeff