On Tue, Mar 13, 2018 at 08:46:26AM +1100, Dave Chinner wrote: > > So maybe we want a layout based swap code instead of reinventing it, > > with the slight twist to the layout break code to never try a lease > > break and just return an error for the IS_SWAPFILE case. > > Hmmm - won't that change user visible behaviour on swapfiles? Not > that it would be a bad thing to reject read/write from root on swap > files, but it would make XFS different to everything else. We already can't writew to active swap files, thank god: root@testvm:~# dd if=/dev/zero of=swapfile bs=1M count=64 64+0 records in 64+0 records out 67108864 bytes (67 MB, 64 MiB) copied, 0.0458446 s, 1.5 GB/s mkswap swapfile mkswap: swapfile: insecure permissions 0644, 0600 suggested. Setting up swapspace version 1, size = 64 MiB (67104768 bytes) no label, UUID=bb42b883-f224-4627-8580-c1ba9f4569ab root@testvm:~# swapon swapfile swapon: /root/swapfile: insecure permissions 0644, 0600 suggested. [ 54.165439] Adding 65532k swap on /root/swapfile. Priority:-2 extents:1 across:65532k root@testvm:~# dd if=/dev/zero of=swapfile bs=1M count=64 dd: failed to open 'swapfile': Text file busy > > Speaking of which - we probably need to spend some time at LSFMM in > the fs track talking about the iomap infrastructure and long term > plans to migrate the major filesystems to it.... I won't be there, as I'll be busy working the local election ballot.
