From: Tao Ma Subject: Re: DIO process stuck apparently due to dioread_nolock (3.0) Date: Sun, 14 Aug 2011 00:02:51 +0800 Message-ID: <1313251371-3672-1-git-send-email-tm@tao.ma> References: <4E456436.8070107@msgid.tls.msk.ru> Cc: mjt@tls.msk.ru, sandeen@redhat.com To: linux-ext4@vger.kernel.org Return-path: Received: from oproxy1-pub.bluehost.com ([66.147.249.253]:46189 "HELO oproxy1-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750956Ab1HMQJY (ORCPT ); Sat, 13 Aug 2011 12:09:24 -0400 In-Reply-To: <4E456436.8070107@msgid.tls.msk.ru> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Tao Ma Hi Michael, could you please check whether this patch work for you? Subject: [PATCH] ext4: Set unwritten flag and increase i_aiodio_unwritten simultaneously. >From 4f1d797973da8b5cf79f58cc1e4d22efb9d46d19 Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Sat, 13 Aug 2011 23:50:28 +0800 Subject: [PATCH] ext4: Set unwritten flag and increase i_aiodio_unwritten simultaneously. EXT4_IO_END_UNWRITTEN flag set and the increase of i_aiodio_unwritten should be done simultaneously since ext4_end_io_nolock always clear the flag and decrease the counter in the same time. We don't increase i_aiodio_unwritten when setting EXT4_IO_END_UNWRITTEN so it will go nagative and causes some process to wait forever. Part of the patch came from Eric in his e-mail. http://marc.info/?l=linux-ext4&m=131316851417460&w=2 Reported-by: Michael Tokarev Signed-off-by: Eric Sandeen Signed-off-by: Tao Ma --- fs/ext4/inode.c | 9 ++++++++- fs/ext4/page-io.c | 6 ++++-- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d47264c..40c0b10 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2668,8 +2668,15 @@ static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate) goto out; } - io_end->flag = EXT4_IO_END_UNWRITTEN; + /* + * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now, + * but being more careful is always safe for the future change. + */ inode = io_end->inode; + if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { + io_end->flag |= EXT4_IO_END_UNWRITTEN; + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); + } /* Add the io_end to per-inode completed io list*/ spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 430c401..78839af 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -334,8 +334,10 @@ submit_and_retry: if ((io_end->num_io_pages >= MAX_IO_PAGES) && (io_end->pages[io_end->num_io_pages-1] != io_page)) goto submit_and_retry; - if (buffer_uninit(bh)) - io->io_end->flag |= EXT4_IO_END_UNWRITTEN; + if (buffer_uninit(bh) && !(io_end->flag & EXT4_IO_END_UNWRITTEN)) { + io_end->flag |= EXT4_IO_END_UNWRITTEN; + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); + } io->io_end->size += bh->b_size; io->io_next_block++; ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh)); -- 1.7.0.4