> > Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> > ---
> > fs/fs-writeback.c | 13 +++++++++++++
> > include/linux/backing-dev.h | 6 ++++++
> > mm/backing-dev.c | 1 +
> > 3 files changed, 20 insertions(+)
> >
> > --- linux-next.orig/fs/fs-writeback.c 2010-07-29 17:13:23.000000000 +0800
> > +++ linux-next/fs/fs-writeback.c 2010-07-29 17:13:49.000000000 +0800
> > @@ -80,6 +80,8 @@ static void bdi_queue_work(struct backin
> >
> > spin_lock(&bdi->wb_lock);
> > list_add_tail(&work->list, &bdi->work_list);
> > + if (work->for_sync)
> > + atomic_inc(&bdi->wb.sync_works);
> > spin_unlock(&bdi->wb_lock);
> >
> > /*
> > @@ -633,6 +635,14 @@ static long wb_writeback(struct bdi_writ
> > break;
> >
> > /*
> > + * background/periodic works can run forever, need to abort
> > + * on seeing any pending sync work, to prevent livelock it.
> > + */
> > + if (atomic_read(&wb->sync_works) &&
> > + (work->for_background || work->for_kupdate))
> > + break;
> > +
> > + /*
> > * For background writeout, stop when we are below the
> > * background dirty threshold
> > */
> > @@ -765,6 +775,9 @@ long wb_do_writeback(struct bdi_writebac
> >
> > wrote += wb_writeback(wb, work);
> >
> > + if (work->for_sync)
> > + atomic_dec(&wb->sync_works);
> > +
> > /*
> > * Notify the caller of completion if this is a synchronous
> > * work item, otherwise just free it.
> > --- linux-next.orig/include/linux/backing-dev.h 2010-07-29 17:13:23.000000000 +0800
> > +++ linux-next/include/linux/backing-dev.h 2010-07-29 17:13:31.000000000 +0800
> > @@ -50,6 +50,12 @@ struct bdi_writeback {
> >
> > unsigned long last_old_flush; /* last old data flush */
> >
> > + /*
> > + * sync works queued, background works shall abort on seeing this,
> > + * to prevent livelocking the sync works
> > + */
> > + atomic_t sync_works;
> > +
> > struct task_struct *task; /* writeback task */
> > struct list_head b_dirty; /* dirty inodes */
> > struct list_head b_io; /* parked for writeback */
> > --- linux-next.orig/mm/backing-dev.c 2010-07-29 17:13:23.000000000 +0800
> > +++ linux-next/mm/backing-dev.c 2010-07-29 17:13:31.000000000 +0800
> > @@ -257,6 +257,7 @@ static void bdi_wb_init(struct bdi_write
> >
> > wb->bdi = bdi;
> > wb->last_old_flush = jiffies;
> > + atomic_set(&wb->sync_works, 0);
> > INIT_LIST_HEAD(&wb->b_dirty);
> > INIT_LIST_HEAD(&wb->b_io);
> > INIT_LIST_HEAD(&wb->b_more_io);
> >
> >
> > --
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> > More majordomo info at
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> --
> Jan Kara <jack@suse.cz>
> SUSE Labs, CR
