From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <20081009174822.406363946@suse.de> References: <20081009155039.139856823@suse.de> Date: Fri, 10 Oct 2008 02:50:42 +1100 From: npiggin@suse.de Subject: [patch 3/8] mm: write_cache_pages writepage error fix Content-Disposition: inline; filename=mm-wcp-writepage-error-fix.patch Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Mikulas Patocka , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org List-ID: In write_cache_pages, if ret signals a real error, but we still have some pages left in the pagevec, done would be set to 1, but the remaining pages would continue to be processed and ret will be overwritten in the process. It could easily be overwritten with success, and thus success will be returned even if there is an error. Thus the caller is told all writes succeeded, wheras in reality some did not. Fix this by bailing immediately if there is an error, and retaining the first error code. This is a data interity bug. Signed-off-by: Nick Piggin --- Index: linux-2.6/mm/page-writeback.c =================================================================== --- linux-2.6.orig/mm/page-writeback.c +++ linux-2.6/mm/page-writeback.c @@ -941,13 +941,17 @@ again: } ret = (*writepage)(page, wbc, data); - if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) { - /* Must retry the write */ - unlock_page(page); - ret = 0; - goto again; + if (unlikely(ret)) { + if (ret == AOP_WRITEPAGE_ACTIVATE) { + /* Must retry the write */ + unlock_page(page); + ret = 0; + goto again; + } + done = 1; + break; } - if (ret || (--(wbc->nr_to_write) <= 0)) + if (--(wbc->nr_to_write) <= 0) done = 1; if (wbc->nonblocking && bdi_write_congested(bdi)) { wbc->encountered_congestion = 1; -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org