Quoting Theodore Ts'o (2025-08-07 23:54:31) > On Wed, Jun 25, 2025 at 09:12:29AM +0200, Anton Khirnov wrote: > > For backups, I want the fs to be static. Back when I wrote this code, it > > seemed reasonable to just make the snapshot read-only, so nothing > > running on the system could modify it accidentally. As it has always > > worked fine until now, I had no reason to dwell on it any further. I > > suppose I drop the '--permission r' option and mount the snapshot -oro > > instead, but the fact that any change is needed at all still strikes me > > as not quite right. > > Apologies for not having time to look into this further until this > week, but thanks to your observations, I was able to find the root > cause of the problem, which is a kernel bug. > > It's a corner case that only happens if (a) you have an unlinked file > which is still has an open file descriptor (which is why we have the > orphan inode list in the first place), (b) during that time, you > freeze the file system while creating a snapshot, and (c) the snapshot > is created read-only (as opposed to just mounting the file system with > the ro mount option). > > The fix is here[1], and should be in the upstream kernel in the next > week or so, and then it will get backported to the LTS kernels, and > from there, hopefully it will end up in the Debian kernel.
Awesome, thanks a lot for the fix. > [1] https://lore.kernel.org/all/[email protected]/ > > BTW, which version of the Debian kernel were you using? The machine is on 6.15-1~exp1 currently, but I intend to update to 6.16 when I can. Cheers, -- Anton Khirnov
