From: David Sterba <dsterba@suse.cz>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Cc: "Reshetova, Elena" <elena.reshetova@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"jbacik@fb.com" <jbacik@fb.com>, "clm@fb.com" <clm@fb.com>,
"dsterba@suse.com" <dsterba@suse.com>
Subject: Re: [PATCH 00/17] fs, btrfs refcount conversions
Date: Thu, 9 Mar 2017 16:29:29 +0100 [thread overview]
Message-ID: <20170309152929.GG14605@twin.jikos.cz> (raw)
In-Reply-To: <2b9ad52c-34fa-1c54-0374-01d443530f63@cn.fujitsu.com>
On Tue, Mar 07, 2017 at 03:49:52PM +0800, Qu Wenruo wrote:
> >>> If the patches pass all tests on your side, could you please take them in and
> >> propagate further?
> >>> I will continue with other kernel subsystems.
> >>
> >> The patchset itself looks like a common cleanup, while I did encounter
> >> several cases (almost all scrub tests) causing kernel warning due to
> >> underflow.
> >
> > Oh, could you please send me the warning outputs? I can hopefully analyze and fix them.
>
> Attached. Which is the generated by running btrfs/070 test case.
> And I canceled the case almost instantly, so output is not much, but
> still contains enough info.
>
> Both refcount_inc() and refcount_sub_and_test() are causing warning.
>
> So now I'm not sure which is the cause, btrfs or bad use of refcount?
We we do atomic_inc to get the first reference after initialization in
scrub_pages, instead of atomic_set (or an equivalent):
2266 spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2267 if (!spage) {
...
2274 }
...
2276 scrub_page_get(spage);
so the references are 0 and refcount_inc will catch that, the fix is simple.
The refcount_sub_and_test reports seem to catch a bug in refcounting, I'm
analyzing it right now.
next prev parent reply other threads:[~2017-03-09 15:30 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-03 8:55 [PATCH 00/17] fs, btrfs refcount conversions Elena Reshetova
2017-03-03 8:55 ` [PATCH 01/17] fs, btrfs: convert btrfs_bio.refs from atomic_t to refcount_t Elena Reshetova
2017-03-03 8:55 ` [PATCH 02/17] fs, btrfs: convert btrfs_transaction.use_count " Elena Reshetova
2017-03-03 8:55 ` [PATCH 03/17] fs, btrfs: convert extent_map.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 04/17] fs, btrfs: convert btrfs_ordered_extent.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 05/17] fs, btrfs: convert btrfs_caching_control.count " Elena Reshetova
2017-03-03 8:55 ` [PATCH 06/17] fs, btrfs: convert btrfs_delayed_ref_node.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 07/17] fs, btrfs: convert btrfs_delayed_node.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 08/17] fs, btrfs: convert btrfs_delayed_item.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 09/17] fs, btrfs: convert btrfs_root.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 10/17] fs, btrfs: convert extent_state.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 11/17] fs, btrfs: convert compressed_bio.pending_bios " Elena Reshetova
2017-03-03 8:55 ` [PATCH 12/17] fs, btrfs: convert scrub_recover.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 13/17] fs, btrfs: convert scrub_page.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 14/17] fs, btrfs: convert scrub_block.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 15/17] fs, btrfs: convert scrub_parity.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 16/17] fs, btrfs: convert scrub_ctx.refs " Elena Reshetova
2017-03-03 8:55 ` [PATCH 17/17] fs, btrfs: convert btrfs_raid_bio.refs " Elena Reshetova
2017-03-06 0:27 ` [PATCH 00/17] fs, btrfs refcount conversions Qu Wenruo
2017-03-06 4:05 ` Qu Wenruo
2017-03-06 9:43 ` Reshetova, Elena
2017-03-07 6:05 ` Qu Wenruo
2017-03-07 7:41 ` Reshetova, Elena
2017-03-07 7:49 ` Qu Wenruo
2017-03-09 15:29 ` David Sterba [this message]
2017-03-09 16:02 ` David Sterba
2017-03-13 10:54 ` Reshetova, Elena
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