Re: [PATCH 4.19 19/71] btrfs: extent_io: add proper error handling to lock_extent_buffer_for_io()

From: Pavel Machek
Date: Wed Nov 11 2020 - 07:44:55 EST


Hi!

> Thankfully it's handled by the only caller, btree_write_cache_pages(),
> as later write_one_eb() call will trigger submit_one_bio(). So there
> shouldn't be any problem.

This explains there should not be any problem in _the
mainline_. AFAICT this talks about this code. Mainline version is:

prev_eb = eb;
ret = lock_extent_buffer_for_io(eb, &epd);
if (!ret) {
free_extent_buffer(eb);
continue;
} else if (ret < 0) {
done = 1;
free_extent_buffer(eb);
break;
}

But 4.19 has:

ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
if (!ret) {
free_extent_buffer(eb);
continue;
}

IOW missing the code mentioned in the changelog. Is 0607eb1d452d4
prerequisite for this patch?

Best regards,
Pavel

> +/*
> + * Lock eb pages and flush the bio if we can't the locks
> + *
> + * Return 0 if nothing went wrong
> + * Return >0 is same as 0, except bio is not submitted
> + * Return <0 if something went wrong, no page is locked
> + */

--
http://www.livejournal.com/~pavelmachek

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