Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753190Ab0KIQpH (ORCPT ); Tue, 9 Nov 2010 11:45:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36640 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792Ab0KIQpE (ORCPT ); Tue, 9 Nov 2010 11:45:04 -0500 Date: Tue, 9 Nov 2010 11:44:22 -0500 From: Rik van Riel To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, esandeen@redhat.com, jmoyer@redhat.com, linux-fsdevel@vger.kernel.org Subject: [PATCH] clear PageError bit in msync & fsync Message-ID: <20101109114422.3918e7f6@annuminas.surriel.com> Organization: Red Hat, Inc. Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2109 Lines: 50 Temporary IO failures, eg. due to loss of both multipath paths, can permanently leave the PageError bit set on a page, resulting in msync or fsync returning -EIO over and over again, even if IO is now getting to the disk correctly. We already clear the AS_ENOSPC and AS_IO bits in mapping->flags in the filemap_fdatawait_range function. Also clearing the PageError bit on the page allows subsequent msync or fsync calls on this file to return without an error, if the subsequent IO succeeds. Unfortunately data written out in the msync or fsync call that returned -EIO can still get lost, because the page dirty bit appears to not get restored on IO error. However, the alternative could be potentially all of memory filling up with uncleanable dirty pages, hanging the system, so there is no nice choice here... Signed-off-by: Rik van Riel diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 5f38c46..4805fde 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -198,7 +198,7 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; } struct page; /* forward declaration */ TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked) -PAGEFLAG(Error, error) +PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error) PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) diff --git a/mm/filemap.c b/mm/filemap.c index 61ba5e4..ba27b83 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -296,7 +296,7 @@ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, continue; wait_on_page_writeback(page); - if (PageError(page)) + if (TestClearPageError(page)) ret = -EIO; } pagevec_release(&pvec); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/