Messages in this thread | | | Date | Thu, 13 Sep 2012 14:39:06 +0800 | From | Fengguang Wu <> | Subject | Re: [PATCH] Fix queueing work if !bdi_cap_writeback_dirty() |
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On Wed, Sep 12, 2012 at 03:28:42AM +0900, OGAWA Hirofumi wrote: > > If bdi has BDI_CAP_NO_WRITEBACK, bdi_forker_thread() doesn't start > writeback thread. This means there is no consumer of work item made > by bdi_queue_work(). > > This adds to checking of !bdi_cap_writeback_dirty(sb->s_bdi) before > calling bdi_queue_work(), otherwise queued work never be consumed. > > Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> > --- > > fs/fs-writeback.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff -puN fs/fs-writeback.c~noop_backing_dev_info-check-fix fs/fs-writeback.c > --- linux/fs/fs-writeback.c~noop_backing_dev_info-check-fix 2012-09-11 06:12:30.000000000 +0900 > +++ linux-hirofumi/fs/fs-writeback.c 2012-09-11 06:12:30.000000000 +0900 > @@ -120,6 +120,9 @@ __bdi_start_writeback(struct backing_dev > { > struct wb_writeback_work *work; > > + if (!bdi_cap_writeback_dirty(bdi)) > + return;
Will someone in the current kernel actually call __bdi_start_writeback() on a BDI_CAP_NO_WRITEBACK bdi?
If the answer is no, VM_BUG_ON(!bdi_cap_writeback_dirty(bdi)) looks better.
Thanks, Fengguang
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