On Mon, Sep 01, 2014 at 02:56:15PM +0800, Miao Xie wrote: > On Fri, 29 Aug 2014 14:31:48 -0400, Chris Mason wrote: > > On 07/29/2014 05:24 AM, Miao Xie wrote: > >> This patch implement data repair function when direct read fails. > >> > >> The detail of the implementation is: > >> - When we find the data is not right, we try to read the data from the > >> other > >> mirror. > >> - After we get right data, we write it back to the corrupted mirror. > >> - And if the data on the new mirror is still corrupted, we will try next > >> mirror until we read right data or all the mirrors are traversed. > >> - After the above work, we set the uptodate flag according to the result. > >> > >> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > >> index 08e65e9..56b1546 100644 > >> --- a/fs/btrfs/disk-io.c > >> +++ b/fs/btrfs/disk-io.c > >> @@ -698,7 +719,12 @@ static void end_workqueue_bio(struct bio *bio, int > >> err) > >> > >> fs_info = end_io_wq->info; > >> end_io_wq->error = err; > >> - btrfs_init_work(&end_io_wq->work, end_workqueue_fn, NULL, NULL); > >> + > >> + if (likely(end_io_wq->metadata != BTRFS_WQ_ENDIO_DIO_REPAIR)) > >> + btrfs_init_work(&end_io_wq->work, end_workqueue_fn, NULL, > >> + NULL); > >> + else > >> + INIT_WORK(&end_io_wq->work.normal_work, dio_end_workqueue_fn); > > > > It's not clear why this one is using INIT_WORK instead of > > btrfs_init_work, or why we're calling directly into queue_work instead > > of btrfs_queue_work. What am I missing? > > I'm sorry that I forgot writing the explanation in this patch's changlog, > I wrote it in Patch 0. > > "2.When the io on the mirror ends, we will insert the endio work into the > system workqueue, not btrfs own endio workqueue, because the original > endio work is still blocked in the btrfs endio workqueue, if we insert > the endio work of the io on the mirror into that workqueue, deadlock > would happen."
Can you elaborate the deadlock? Now that buffer read can insert a subsequent read-mirror bio into btrfs endio workqueue without problems, what's the difference? thanks, -liubo > > Could you add it into the changelog of this patch when you apply this patch? > > Thanks > Miao > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
