On Fri, Jun 03, 2016 at 12:08:38PM -0700, Liu Bo wrote: > eb->io_pages is set in read_extent_buffer_pages(). > > In case of readpage failure, for pages that have been added to bio, > it calls bio_endio and later readpage_io_failed_hook() does the work. > > When this eb's page (couldn't be the 1st page) fails to add itself to bio > due to failure in merge_bio(), it cannot decrease eb->io_pages via bio_endio, > and ends up with a memory leak eventually. > > This lets __do_readpage propagate errors to callers and adds the > 'atomic_dec(&eb->io_pages)'.
I'm not sure, but could we lose some error values from __do_readpage? Ie. return 0 even if there was an error in a page that's in the middle (not the first, not the last). The loop in __do_readpage iterates while (cur <= end), and ret is only set by submit_extent_page, but the loop does not exit immediatelly. So we can detect error, set page error state bit, but next loop will overwrite ret with 0 (if the page submission was ok). Then we still don't decrement the io_pages as needed. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
