Re: [PATCH -v2] ext4: inline jbd2_journal_[un]register_shrinker()

Jon Hunter
2021-07-05T18:29:26Z

On 05/07/2021 15:50, Theodore Ts'o wrote:
> The function jbd2_journal_unregister_shrinker() was getting called
> twice when the file system was getting unmounted. On Power and ARM
> platforms this was causing kernel crash when unmounting the file
> system, when a percpu_counter was destroyed twice.
>
> Fix this by removing jbd2_journal_[un]register_shrinker() functions,
> and inlining the shrinker setup and teardown into
> journal_init_common() and jbd2_journal_destroy(). This means that
> ext4 and ocfs2 now no longer need to know about registering and
> unregistering jbd2's shrinker.
>
> Also, while we're at it, rename the percpu counter from
> j_jh_shrink_count to j_checkpoint_jh_count, since this makes it
> clearer what this counter is intended to track.
>
> Fixes: 4ba3fcdde7e3 ("jbd2,ext4: add a shrinker to release checkpointed buffers")
> Reported-by: Jon Hunter <jonathanh@nvidia.com>
> Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Thanks, works for me.

Tested-by: Jon Hunter <jonathanh@nvidia.com>

Cheers
Jon

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