Messages in this thread | | | Date | Tue, 3 May 2016 11:58:46 -0400 | From | Waiman Long <> | Subject | Re: [RFC PATCH] ext4: Don't release mutex for DAX write |
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On 05/03/2016 04:43 AM, Christoph Hellwig wrote: > As explained in another thread I really think we need to get DAX > to stop pretending to be direct I/O, which should also take care > of the locking. The same issue also exists for ext2 and XFS so it > needs to be solved at a higher level.
I think the DAX code was in the DIO path because it didn't want to use buffer cache at all. Taking DAX out from DIO will mean having a third mode of doing I/O which is similar to DIO in certain ways, but not exactly the same. There will be a certain amount of code duplication in this case. Do we really want to do that?
As for the locking problem, xfs doesn't seem to have issue as it uses a rwsem in the xfs inode for synchronization. I haven't looked into the ext2 code to see if there is any issue there.
Cheers, Longman
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