From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails.patch added to -mm tree Date: Thu, 21 Aug 2008 14:21:11 -0700 Message-ID: <200808212121.m7LLLCgV026546@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:60644 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755321AbYHUV0u (ORCPT ); Thu, 21 Aug 2008 17:26:50 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: hifumi.hisashi@oss.ntt.co.jp, chris.mason@oracle.com, cmm@us.ibm.com, jack@suse.cz, zach.brown@oracle.com The patch titled VFS: fix dio write returning EIO when try_to_release_page fails has been added to the -mm tree. Its filename is vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: VFS: fix dio write returning EIO when try_to_release_page fails From: Hisashi Hifumi Dio write returns EIO when try_to_release_page fails because bh is still referenced. The patch commit 3f31fddfa26b7594b44ff2b34f9a04ba409e0f91 Author: Mingming Cao Date: Fri Jul 25 01:46:22 2008 -0700 jbd: fix race between free buffer and commit transaction was merged into 2.6.27-rc1, but I noticed that this patch is not enough to fix the race. I did fsstress test heavily to 2.6.27-rc1, and found that dio write still sometimes got EIO through this test. The patch above fixed race between freeing buffer(dio) and committing transaction(jbd) but I discovered that there is another race, freeing buffer(dio) and ext3/4_ordered_writepage. : background_writeout() ->write_cache_pages() ->ext3_ordered_writepage() walk_page_buffers() -> take a bh ref block_write_full_page() -> unlock_page : <- end_page_writeback : <- race! (dio write->try_to_release_page fails) walk_page_buffers() ->release a bh ref ext3_ordered_writepage holds bh ref and does unlock_page remaining taking a bh ref, so this causes the race and failure of try_to_release_page. To fix this race, I used the approach of falling back to buffered writes if try_to_release_page() fails on a page. Signed-off-by: Hisashi Hifumi Cc: Chris Mason Cc: Jan Kara Cc: Mingming Cao Cc: Zach Brown Signed-off-by: Andrew Morton --- mm/filemap.c | 11 +++++++++-- mm/truncate.c | 4 ++-- 2 files changed, 11 insertions(+), 4 deletions(-) diff -puN mm/filemap.c~vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails mm/filemap.c --- a/mm/filemap.c~vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails +++ a/mm/filemap.c @@ -2129,13 +2129,20 @@ generic_file_direct_write(struct kiocb * * After a write we want buffered reads to be sure to go to disk to get * the new data. We invalidate clean cached page from the region we're * about to write. We do this *before* the write so that we can return - * -EIO without clobbering -EIOCBQUEUED from ->direct_IO(). + * without clobbering -EIOCBQUEUED from ->direct_IO(). */ if (mapping->nrpages) { written = invalidate_inode_pages2_range(mapping, pos >> PAGE_CACHE_SHIFT, end); - if (written) + /* + * If a page can not be invalidated, return 0 to fall back + * to buffered write. + */ + if (written) { + if (written == -EBUSY) + return 0; goto out; + } } written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs); diff -puN mm/truncate.c~vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails mm/truncate.c --- a/mm/truncate.c~vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails +++ a/mm/truncate.c @@ -380,7 +380,7 @@ static int do_launder_page(struct addres * Any pages which are found to be mapped into pagetables are unmapped prior to * invalidation. * - * Returns -EIO if any pages could not be invalidated. + * Returns -EBUSY if any pages could not be invalidated. */ int invalidate_inode_pages2_range(struct address_space *mapping, pgoff_t start, pgoff_t end) @@ -440,7 +440,7 @@ int invalidate_inode_pages2_range(struct ret2 = do_launder_page(mapping, page); if (ret2 == 0) { if (!invalidate_complete_page2(mapping, page)) - ret2 = -EIO; + ret2 = -EBUSY; } if (ret2 < 0) ret = ret2; _ Patches currently in -mm which might be from hifumi.hisashi@oss.ntt.co.jp are vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails.patch vfs-fix-dio-write-returning-eio-when-try_to_release_page-fails-fix.patch vmscan-set-try_to_release_pages-gfp_mask-to-0.patch