> On Jun 21, 2019, at 4:37 PM, Warner Losh <i...@bsdimp.com> wrote: > > On Fri, Jun 21, 2019, 3:33 PM Conrad Meyer <c...@freebsd.org> wrote: > >> On Fri, Jun 21, 2019 at 2:55 PM Alan Somers <asom...@freebsd.org> wrote: >>> I would've thought that immediately following a sync(8), the >>> filesystem would be consistent. Why do I still see errors after a >>> panic in files that were written before I sync()ed? >>> -Alan >> >> Hi Alan, >> >> Contra the name, sync(2) (sync(8)) isn't synchronous. It invokes >> VFS_SYNC() with MNT_NOWAIT across all mountpoints. >> > > Yes. Sync(2) just starts the I/O, but it may be delayed if there is a lot > of dirty buffers. The other issue is that new buffers may be dirtied… >
Still, the point of SU and SU+J is that the filesystem should not be damaged and require active repair on reboot, whether or not a sync or fsync was done. There’s certainly issues with disk lying about out of order writes, POSIX sematics of unlinked files, and the inherent design of UFS superblock updates, but the problems that Alan reported should still be looked at, they’re not expected and they undermine the usefulness of SU+J. Scott _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
