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Commit 27a353c0 authored by Shaohua Li's avatar Shaohua Li
Browse files

RAID5: check_reshape() shouldn't call mddev_suspend 



check_reshape() is called from raid5d thread. raid5d thread shouldn't
call mddev_suspend(), because mddev_suspend() waits for all IO finish
but IO is handled in raid5d thread, we could easily deadlock here.

This issue is introduced by
738a2738 ("md/raid5: fix allocation of 'scribble' array.")

Cc: stable@vger.kernel.org (v4.1+)
Reported-and-tested-by: default avatarArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Reviewed-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent e7597e69

drivers/md/raid5.c

+18 −0
Original line number Diff line number Diff line
@@ -2089,6 +2089,14 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors) 
	unsigned long cpu;

	int err = 0;



	/*

	 * Never shrink. And mddev_suspend() could deadlock if this is called

	 * from raid5d. In that case, scribble_disks and scribble_sectors

	 * should equal to new_disks and new_sectors

	 */

	if (conf->scribble_disks >= new_disks &&

	    conf->scribble_sectors >= new_sectors)

		return 0;

	mddev_suspend(conf->mddev);

	get_online_cpus();

	for_each_present_cpu(cpu) {
@@ -2110,6 +2118,10 @@ static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors) 
	}

	put_online_cpus();

	mddev_resume(conf->mddev);

	if (!err) {

		conf->scribble_disks = new_disks;

		conf->scribble_sectors = new_sectors;

	}

	return err;

}
@@ -6413,6 +6425,12 @@ static int raid5_alloc_percpu(struct r5conf *conf) 
	}

	put_online_cpus();



	if (!err) {

		conf->scribble_disks = max(conf->raid_disks,

			conf->previous_raid_disks);

		conf->scribble_sectors = max(conf->chunk_sectors,

			conf->prev_chunk_sectors);

	}

	return err;

}

drivers/md/raid5.h

+2 −0
Original line number Diff line number Diff line
@@ -510,6 +510,8 @@ struct r5conf { 
					      * conversions

					      */

	} __percpu *percpu;

	int scribble_disks;

	int scribble_sectors;

#ifdef CONFIG_HOTPLUG_CPU

	struct notifier_block	cpu_notify;

#endif