Messages in this thread | | | Date | Fri, 10 Feb 2017 17:02:08 +0100 | From | David Sterba <> | Subject | Re: [PATCH v2] Btrfs: add another missing end_page_writeback on submit_extent_page failure |
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On Thu, Feb 09, 2017 at 05:24:33PM +0900, Takafumi Kubota wrote: > If btrfs_bio_alloc fails in submit_extent_page, submit_extent_page returns > without clearing the writeback bit of the failed page. > > __extent_writepage_io, that is a caller of submit_extent_page, > does not clear the remaining writeback bit anywhere. > As a result, this will cause the hang at filemap_fdatawait_range, > because it waits the writeback bit to be cleared from the failed page. > So, we have to call end_page_writeback to clear the writeback bit. > > For reproducing the hang, we inject a fault like > > if (should_failtest()) { // I define should_failtest() > bio = NULL; > } > else { > bio = btrfs_bio_alloc(...); > } > > in submit_extent_page. > > We should also check whether page has the bit before end_page_writeback, > to avoid the conflict against the other end_page_writeback in bio_endio. > Thus, we add PageWriteback checks not only in __extent_writepage_io, > but also in write_one_eb too, because it misses the check. > > Signed-off-by: Takafumi Kubota <takafumi.kubota1012@sslab.ics.keio.ac.jp> > Reviewed-by: Liu Bo <bo.li.liu@oracle.com> > Cc: David Sterba <dsterba@suse.cz>
Added to 4.11 queue, thanks.
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