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From: Andrew Morton <akpm@osdl.org>
To: NeilBrown <neilb@cse.unsw.edu.au>
Cc: linux-raid@vger.kernel.org
Subject: Re: [PATCH md 6 of 6] Fix handling of overlapping requests in raid5
Date: Mon, 7 Feb 2005 18:24:56 -0800	[thread overview]
Message-ID: <20050207182456.1d50c83b.akpm@osdl.org> (raw)
In-Reply-To: <E1Cxyst-0004fu-PP@notabene.cse.unsw.edu.au>

NeilBrown <neilb@cse.unsw.edu.au> wrote:
>
> +	retry:
>   		sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK));
>   		if (sh) {
>  -
>  -			while (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
>  -				/* add failed due to overlap.  Flush everything
>  +			if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
>  +				/* Add failed due to overlap.  Flush everything
>   				 * and wait a while
>  -				 * FIXME - overlapping requests should be handled better
>   				 */
>   				raid5_unplug_device(mddev->queue);
>  -				set_current_state(TASK_UNINTERRUPTIBLE);
>  -				schedule_timeout(1);
>  +				release_stripe(sh);
>  +				schedule();
>  +				goto retry;

Worrisome.  If the calling process has SCHED_RR or SCHED_FIFO policy, this
could cause a lockup, perhaps.

Some sort of real synchronisation scheme would be nicer.  Or at the least,
what was wrong with the schedule_timeout(1)?

  reply	other threads:[~2005-02-08  2:24 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-02-07  2:44 [PATCH md 0 of 6] Introduction NeilBrown
2005-02-07  2:44 ` [PATCH md 3 of 6] Make md work a bit better with devfs NeilBrown
2005-02-07  2:44 ` [PATCH md 4 of 6] Fix endless loop when syncing an array that doesn't need any resync NeilBrown
2005-02-07  2:44 ` [PATCH md 2 of 6] Prevent oops when drive set faulty in inactive md array NeilBrown
2005-02-07  2:44 ` [PATCH md 5 of 6] Remove extra loop from copy_data NeilBrown
2005-02-07  2:44 ` [PATCH md 1 of 6] Fix problems with verion-1 superblock code NeilBrown
2005-02-07  2:44 ` [PATCH md 6 of 6] Fix handling of overlapping requests in raid5 NeilBrown
2005-02-08  2:24   ` Andrew Morton [this message]
2005-02-08  2:39     ` Neil Brown
2005-02-08  3:07       ` Andrew Morton

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