Re: [RFC 01/16] NOVA: Documentation

2017-08-05 Thread Steven Swanson
There is nothing impossible COW for mapped files, but it is not a good match for the expected usage model for DAX. The idea is that programs can mmap files and the build interesting data structures in them, just like they do in DRAM. This means lots of small updatEs, and that would be very

Re: [PATCH v2 1/5] fs, xfs: introduce S_IOMAP_IMMUTABLE

2017-08-05 Thread Christoph Hellwig
NAK^4. We should not allow users to create immutable files. We have proper ways to synchronize I/O, and this is just an invitation for horrible abuses that should not be allowed, and which we've always people told not to do. ___ Linux-nvdimm mailing

Re: [PATCH 1/3] fs, xfs: introduce S_IOMAP_IMMUTABLE

2017-08-05 Thread Christoph Hellwig
On Tue, Aug 01, 2017 at 12:42:18PM +1000, Dave Chinner wrote: > I've outlined other use cases in previous discussions. To repeat > myself, every so often we get someone with, say, a new high > speed camera that want to dma the camera frames direct to the > storage because they can't push 500,000

Re: [PATCH v2 0/5] fs, xfs: block map immutable files for dax, dma-to-storage, and swap

2017-08-05 Thread Christoph Hellwig
On Thu, Aug 03, 2017 at 07:38:11PM -0700, Dan Williams wrote: > [ adding linux-api to the cover letter for notification, will send the > full set to linux-api for v3 ] Just don't send this crap ever again. All the so called use cases in the earlier thread were incorrect and highly dangerous.