Re: [PATCH] lib/ext2fs: Validity checks for ext2fs_inode_scan_goto_blockgroup()

Darrick J. Wong
2023-12-02T17:10:45Z

On Fri, Dec 01, 2023 at 09:30:38AM -0800, Brian Norris wrote:
> On Fri, Dec 1, 2023 at 8:24 AM Darrick J. Wong <djwong@kernel.org> wrote:
> > On Thu, Nov 30, 2023 at 04:01:18PM -0800, Brian Norris wrote:
> > > This resolves issues seen in ureadahead, when it uses an old packfile
> > > (with mismatching group indices) with a new filesystem.
> >
> > Say what now? The boot time pre-caching thing Ubuntu used to have?
> > https://manpages.ubuntu.com/manpages/trusty/man8/ureadahead.8.html
>
> Sure. ChromeOS still uses it. Steven Rostedt even bothered to do a
> talk about it recently:
> https://eoss2023.sched.com/event/1LcMw/the-resurrection-of-ureadahead-and-speeding-up-the-boot-process-and-preloading-applications-steven-rostedt-google

Wow. I had no idea that ureadahead reads the inode blocks of a mounted
ext* filesystem into the page cache. Welp, it's a good thing those are
part of the static layout.

Anyway, this fix looks correct to me, so I don't see any reason to hold
this up...
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

>
> Brian
>