From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com ([141.146.126.79]:52929 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751827AbdLIAMn (ORCPT ); Fri, 8 Dec 2017 19:12:43 -0500 Date: Fri, 8 Dec 2017 16:05:39 -0700 From: Liu Bo To: linux-btrfs@vger.kernel.org Cc: =?iso-8859-1?B?Suly9G1l?= Carretero Subject: Re: [PATCH] Btrfs: raid56: fix race between merge_bio and rbio_orig_end_io Message-ID: <20171208230539.GA30998@dhcp-10-211-47-181.usdhcp.oraclecorp.com> Reply-To: bo.li.liu@oracle.com References: <20171208230235.30636-1-bo.li.liu@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <20171208230235.30636-1-bo.li.liu@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: (Add Jérôme Carretero.) Thanks, -liubo On Fri, Dec 08, 2017 at 04:02:35PM -0700, Liu Bo wrote: > We're not allowed to take any new bios to rbio->bio_list in > rbio_orig_end_io(), otherwise we may get merged with more bios and > rbio->bio_list is not empty. > > This should only happens in error-out cases, the normal path of > recover and full stripe write have already set RBIO_RMW_LOCKED_BIT to > disable merge before doing IO. > > Reported-by: Jérôme Carretero > Signed-off-by: Liu Bo > --- > fs/btrfs/raid56.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c > index 5aa9d22..127c782 100644 > --- a/fs/btrfs/raid56.c > +++ b/fs/btrfs/raid56.c > @@ -859,12 +859,23 @@ static void free_raid_bio(struct btrfs_raid_bio *rbio) > */ > static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err) > { > - struct bio *cur = bio_list_get(&rbio->bio_list); > + struct bio *cur; > struct bio *next; > > + /* > + * We're not allowed to take any new bios to rbio->bio_list > + * from now on, otherwise we may get merged with more bios and > + * rbio->bio_list is not empty. > + */ > + spin_lock(&rbio->bio_list_lock); > + set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); > + spin_unlock(&rbio->bio_list_lock); > + > if (rbio->generic_bio_cnt) > btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt); > > + cur = bio_list_get(&rbio->bio_list); > + > free_raid_bio(rbio); > > while (cur) { > -- > 2.9.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html