Re: Implementing NVMHCI...

From: Avi Kivity
Date: Tue Apr 14 2009 - 08:11:05 EST


Jeff Garzik wrote:
(c) export information indicating the true sector size, in a manner similar to how the ATA driver passes that info to userland partitioning tools.

Eventually we'll want to allow filesystems to make use of the native sector size.

At the kernel level, you mean?


Yes. You'll want to align extents and I/O requests on that boundary.


But if you are talking about filesystems directly supporting sector sizes >4kb, well, I'll let Linus and others settle that debate :) I will just write the driver once the dust settles...

IMO drivers should expose whatever sector size the device have, filesystems should expose their block size, and the block layer should correct any impedance mismatches by doing RMW.

Unfortunately, sector size > fs block size means a lot of pointless locking for the RMW, so if large sector sizes take off, we'll have to adjust filesystems to use larger block sizes.

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