On Fri, Apr 19, 2024 at 7:19 PM Kent Overstreet <[email protected]> wrote: > > On Fri, Apr 19, 2024 at 10:35:27AM +0200, Dmitry Vyukov wrote: > > > > We've enabled the configs, but we don't have good image seeds yet. > > Aleksandr tried to generate them, he is currently OOO, but maybe you > > can help meanwhile. > > He said that running: > > > > $ mkfs.bcachefs test.img > > > > gives this error (on a quite big image, I don't know how large exactly it > > was): > > > > insufficient space for superblocks: start 8 end 4104 > 4096 size 2048 > > > > Why could it give such an error and how to avoid it? > > What was the precise size? I'll see if I'm able to reproduce
I think the problem was that I was trying to save the generated files to a 9p filesystem (so that I could easily take them out of my VM). But now I've set up a proper userspace image with the latest 6.9 RC kernel and it worked fine. > > > Also what would be a good sets of options to generate seed images? > > We try to "sample" space of different images to create seeds. To give > > you an idea here is what we do for other file systems: > > https://github.com/google/syzkaller/blob/af24b0505c748561efb50f1d03c824d6642f6c0b/tools/syz-imagegen/imagegen.go#L60-L516 > > --encrypted --no_passphrase > --compression=lz4 > --no-checksum The mkfs.bcachefs tool that I installed does not know the --no-checksum flag, so I used --data_checksum=none --metadata_checksum=none instead. Does it mean the same thing? I've pushed my changes to https://github.com/google/syzkaller/pull/4752 -- Aleksandr > > That shousd get us reasonable coverage to start with.
