On Wed, Jun 07, 2017 at 05:35:31PM -0700, Richard Narron wrote: > I am willing to test. I just turned on UFS_FS_WRITE for the very first time > running 4.12-rc4 and was able to copy a file of more than 2GB from one r/o > FreeBSD subpartition to another r/w FreeBSD subpartition. > > So it is already looking pretty good. The nasty cases are around short files, especially short files with holes. Linear writes as done by cp(1) will do nothing worse than bogus i_blocks (and possibly mangled counters in cylinder groups). Random write access to short files, OTOH, steps into a lot more codepaths... As for ->i_blocks, it triggers this: root@kvm1:/mnt# df .; mkdir a; rmdir a; df . Filesystem 1K-blocks Used Available Use% Mounted on /dev/loop0 507420 4504 462340 1% /mnt Filesystem 1K-blocks Used Available Use% Mounted on /dev/loop0 507420 4536 462308 1% /mnt Note the 32Kb (== one block on that ufs2) leaked here. Every iteration will leak another one. Similar for long symlinks...
