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>
Signed-off-by: David Sterba <dsterba@suse.com>
fe01aa6538