From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:39707 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932114AbdJJRtO (ORCPT ); Tue, 10 Oct 2017 13:49:14 -0400 Date: Tue, 10 Oct 2017 10:45:01 -0700 From: Liu Bo To: Tejun Heo Cc: jack@suse.cz, axboe@kernel.dk, clm@fb.com, jbacik@fb.com, kernel-team@fb.com, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: Re: [PATCH v2 5/5] btrfs: ensure that metadata and flush are issued from the root cgroup Message-ID: <20171010174501.GD32758@lim.localdomain> Reply-To: bo.li.liu@oracle.com References: <20171010155441.753966-1-tj@kernel.org> <20171010155441.753966-6-tj@kernel.org> <20171010164325.GN3301751@devbig577.frc2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20171010164325.GN3301751@devbig577.frc2.facebook.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Tue, Oct 10, 2017 at 09:43:26AM -0700, Tejun Heo wrote: > From 3bbed8c7747739cda48f592f165e8839da076a3a Mon Sep 17 00:00:00 2001 > > Issuing metdata or otherwise shared IOs from !root cgroup can lead to > priority inversion. This patch ensures that those IOs are always > issued from the root cgroup. > > This patch updates btrfs_update_iflags() to not set S_CGROUPWB on > btree_inodes. This isn't strictly necessary as those inodes don't > call the function during init; however, this serves as documentation > and prevents possible future mistakes. If this isn't desirable, > please feel free to drop the section. > > v2: Fixed missing @bh in submit_bh_blkcg_css() call. > Looks good. Reviewed-by: Liu Bo -liubo > Signed-off-by: Tejun Heo > Cc: Chris Mason > Cc: Josef Bacik > --- > fs/btrfs/check-integrity.c | 2 +- > fs/btrfs/disk-io.c | 4 ++++ > fs/btrfs/ioctl.c | 4 +++- > 3 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c > index 7d5a9b5..d66774e 100644 > --- a/fs/btrfs/check-integrity.c > +++ b/fs/btrfs/check-integrity.c > @@ -2741,7 +2741,7 @@ int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh) > struct btrfsic_dev_state *dev_state; > > if (!btrfsic_is_initialized) > - return submit_bh(op, op_flags, bh); > + return submit_bh_blkcg_css(op, op_flags, bh, blkcg_root_css); > > mutex_lock(&btrfsic_mutex); > /* since btrfsic_submit_bh() might also be called before > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index dfdab84..fe8bbe1 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -1025,6 +1025,8 @@ static blk_status_t btree_submit_bio_hook(void *private_data, struct bio *bio, > int async = check_async_write(bio_flags); > blk_status_t ret; > > + bio_associate_blkcg(bio, blkcg_root_css); > + > if (bio_op(bio) != REQ_OP_WRITE) { > /* > * called for a read, do the setup so that checksum validation > @@ -3512,6 +3514,8 @@ static void write_dev_flush(struct btrfs_device *device) > return; > > bio_reset(bio); > + bio_associate_blkcg(bio, blkcg_root_css); > + > bio->bi_end_io = btrfs_end_empty_barrier; > bio_set_dev(bio, device->bdev); > bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH; > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index 117cc63..8a7db6c 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -150,7 +150,9 @@ void btrfs_update_iflags(struct inode *inode) > new_fl |= S_NOATIME; > if (ip->flags & BTRFS_INODE_DIRSYNC) > new_fl |= S_DIRSYNC; > - new_fl |= S_CGROUPWB; > + /* btree_inodes are always in the root cgroup */ > + if (btrfs_ino(ip) != BTRFS_BTREE_INODE_OBJECTID) > + new_fl |= S_CGROUPWB; > > set_mask_bits(&inode->i_flags, > S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC | > -- > 2.9.5 > > -- > 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