On Thu, Aug 18, 2016 at 11:33 PM, Omar Sandoval <osandov@xxxxxxxxxxx> wrote: > On Tue, Jul 19, 2016 at 03:25:16PM -0400, Chris Mason wrote: >> On 07/19/2016 12:06 PM, Chandan Rajendra wrote: >> >> Omar, looks like we need to make the patched kernel refuse to mount free >> space trees without a new incompat bit set. That way there won't be any >> surprises for the people that have managed to get a free space tree saved. >> Can it please printk a message about clearing the tree and mounting again? >> > Sorry it took me a month to get around to this, I tried to implement > this a couple of ways but I really don't like it. Basically, when we see > that we're missing the compat bit, we have to assume that the free space > tree was created with the same endianness that we're running on now. > That could lead to a false positive if, say, we created the filesystem > on a little-endian machine with an old kernel but are using it on a > big-endian system, or a false negative if it was created on a big-endian > machine with an old kernel but we're using it on a little-endian > machine. > > There's also the question of making it a compat bit vs an incompat bit. > An incompat bit makes sure that we don't break the filesystem by > mounting it on an old big-endian kernel, but needlessly breaks > backwards-compatibility for little-endian. > > I'd be much happier if we could just pretend this never happened. Here's > the patch, anyways, for the sake of completeness. Chris, what do you > think? Omar, I can't load btrfs module with this patch applied to 4.8.0-rc3+ (git v4.8-rc3-39-g61c0457) on "modprobe btrfs" i'm getting the following in the logs and module does not load: Btrfs loaded, crc32c=crc32c-generic, debug=on, assert=on BTRFS: selftest: sectorsize: 8192 nodesize: 8192 BTRFS: selftest: Running btrfs free space cache tests BTRFS: selftest: Running extent only tests BTRFS: selftest: Running bitmap only tests BTRFS: selftest: Running bitmap and extent tests BTRFS: selftest: Running space stealing from bitmap to extent BTRFS: selftest: Free space cache tests finished BTRFS: selftest: Running extent buffer operation tests BTRFS: selftest: Running btrfs_split_item tests BTRFS: selftest: Running extent I/O tests BTRFS: selftest: Running find delalloc tests BTRFS: selftest: Running extent buffer bitmap tests BTRFS: selftest: Setting straddling pages failed BTRFS: selftest: Extent I/O tests finished -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
