Commit 850b2b42 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

[PATCH] md: replace magic numbers in sb_dirty with well defined bit flags 



Instead of magic numbers (0,1,2,3) in sb_dirty, we have
some flags instead:
MD_CHANGE_DEVS
   Some device state has changed requiring superblock update
   on all devices.
MD_CHANGE_CLEAN
   The array has transitions from 'clean' to 'dirty' or back,
   requiring a superblock update on active devices, but possibly
   not on spares
MD_CHANGE_PENDING
   A superblock update is underway.

We wait for an update to complete by waiting for all flags to be clear.  A
flag can be set at any time, even during an update, without risk that the
change will be lost.

Stop exporting md_update_sb - isn't needed.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6814d536

drivers/md/md.c

+40 −36
Original line number Diff line number Diff line
@@ -1587,7 +1587,7 @@ static void sync_sbs(mddev_t * mddev, int nospares) 
	}

}



void md_update_sb(mddev_t * mddev)

static void md_update_sb(mddev_t * mddev, int force_change)

{

	int err;

	struct list_head *tmp;
@@ -1598,7 +1598,18 @@ void md_update_sb(mddev_t * mddev) 
repeat:

	spin_lock_irq(&mddev->write_lock);



	if (mddev->degraded && mddev->sb_dirty == 3)

	set_bit(MD_CHANGE_PENDING, &mddev->flags);

	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))

		force_change = 1;

	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))

		/* just a clean<-> dirty transition, possibly leave spares alone,

		 * though if events isn't the right even/odd, we will have to do

		 * spares after all

		 */

		nospares = 1;

	if (force_change)

		nospares = 0;

	if (mddev->degraded)

		/* If the array is degraded, then skipping spares is both

		 * dangerous and fairly pointless.

		 * Dangerous because a device that was removed from the array
@@ -1608,20 +1619,14 @@ repeat: 
		 * then a recovery will happen and soon that array won't

		 * be degraded any more and the spare can go back to sleep then.

		 */

		mddev->sb_dirty = 1;

		nospares = 0;



	sync_req = mddev->in_sync;

	mddev->utime = get_seconds();

	if (mddev->sb_dirty == 3)

		/* just a clean<-> dirty transition, possibly leave spares alone,

		 * though if events isn't the right even/odd, we will have to do

		 * spares after all

		 */

		nospares = 1;



	/* If this is just a dirty<->clean transition, and the array is clean

	 * and 'events' is odd, we can roll back to the previous clean state */

	if (mddev->sb_dirty == 3

	if (nospares

	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)

	    && (mddev->events & 1))

		mddev->events--;
@@ -1652,7 +1657,6 @@ repeat: 
		MD_BUG();

		mddev->events --;

	}

	mddev->sb_dirty = 2;

	sync_sbs(mddev, nospares);



	/*
@@ -1660,7 +1664,7 @@ repeat: 
	 * nonpersistent superblocks

	 */

	if (!mddev->persistent) {

		mddev->sb_dirty = 0;

		clear_bit(MD_CHANGE_PENDING, &mddev->flags);

		spin_unlock_irq(&mddev->write_lock);

		wake_up(&mddev->sb_wait);

		return;
@@ -1697,20 +1701,20 @@ repeat: 
			break;

	}

	md_super_wait(mddev);

	/* if there was a failure, sb_dirty was set to 1, and we re-write super */

	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */



	spin_lock_irq(&mddev->write_lock);

	if (mddev->in_sync != sync_req|| mddev->sb_dirty == 1) {

	if (mddev->in_sync != sync_req ||

	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {

		/* have to write it out again */

		spin_unlock_irq(&mddev->write_lock);

		goto repeat;

	}

	mddev->sb_dirty = 0;

	clear_bit(MD_CHANGE_PENDING, &mddev->flags);

	spin_unlock_irq(&mddev->write_lock);

	wake_up(&mddev->sb_wait);



}

EXPORT_SYMBOL_GPL(md_update_sb);



/* words written to sysfs files may, or my not, be \n terminated.

 * We want to accept with case. For this we use cmd_match.
@@ -1783,7 +1787,7 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len) 
		else {

			mddev_t *mddev = rdev->mddev;

			kick_rdev_from_array(rdev);

			md_update_sb(mddev);

			md_update_sb(mddev, 1);

			md_new_event(mddev);

			err = 0;

		}
@@ -2426,7 +2430,7 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len) 
			spin_lock_irq(&mddev->write_lock);

			if (atomic_read(&mddev->writes_pending) == 0) {

				mddev->in_sync = 1;

				mddev->sb_dirty = 1;

				set_bit(MD_CHANGE_CLEAN, &mddev->flags);

			}

			spin_unlock_irq(&mddev->write_lock);

		} else {
@@ -2438,7 +2442,7 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len) 
	case active:

		if (mddev->pers) {

			restart_array(mddev);

			mddev->sb_dirty = 0;

			clear_bit(MD_CHANGE_CLEAN, &mddev->flags);

			wake_up(&mddev->sb_wait);

			err = 0;

		} else {
@@ -2543,7 +2547,7 @@ size_store(mddev_t *mddev, const char *buf, size_t len) 


	if (mddev->pers) {

		err = update_size(mddev, size);

		md_update_sb(mddev);

		md_update_sb(mddev, 1);

	} else {

		if (mddev->size == 0 ||

		    mddev->size > size)
@@ -3111,8 +3115,8 @@ static int do_md_run(mddev_t * mddev) 
	

	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);

	

	if (mddev->sb_dirty)

		md_update_sb(mddev);

	if (mddev->flags)

		md_update_sb(mddev, 0);



	set_capacity(disk, mddev->array_size<<1);
@@ -3275,10 +3279,10 @@ static int do_md_stop(mddev_t * mddev, int mode) 
			if (mddev->ro)

				mddev->ro = 0;

		}

		if (!mddev->in_sync || mddev->sb_dirty) {

		if (!mddev->in_sync || mddev->flags) {

			/* mark array as shutdown cleanly */

			mddev->in_sync = 1;

			md_update_sb(mddev);

			md_update_sb(mddev, 1);

		}

		if (mode == 1)

			set_disk_ro(disk, 1);
@@ -3747,7 +3751,7 @@ static int hot_remove_disk(mddev_t * mddev, dev_t dev) 
		goto busy;



	kick_rdev_from_array(rdev);

	md_update_sb(mddev);

	md_update_sb(mddev, 1);

	md_new_event(mddev);



	return 0;
@@ -3824,7 +3828,7 @@ static int hot_add_disk(mddev_t * mddev, dev_t dev) 


	rdev->raid_disk = -1;



	md_update_sb(mddev);

	md_update_sb(mddev, 1);



	/*

	 * Kick recovery, maybe this spare has to be added to the
@@ -3955,7 +3959,8 @@ static int set_array_info(mddev_t * mddev, mdu_array_info_t *info) 


	mddev->max_disks     = MD_SB_DISKS;



	mddev->sb_dirty      = 1;

	mddev->flags         = 0;

	set_bit(MD_CHANGE_DEVS, &mddev->flags);



	mddev->default_bitmap_offset = MD_SB_BYTES >> 9;

	mddev->bitmap_offset = 0;
@@ -4124,7 +4129,7 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info) 
			mddev->bitmap_offset = 0;

		}

	}

	md_update_sb(mddev);

	md_update_sb(mddev, 1);

	return rv;

}
@@ -4960,12 +4965,12 @@ void md_write_start(mddev_t *mddev, struct bio *bi) 
		spin_lock_irq(&mddev->write_lock);

		if (mddev->in_sync) {

			mddev->in_sync = 0;

			mddev->sb_dirty = 3;

			set_bit(MD_CHANGE_CLEAN, &mddev->flags);

			md_wakeup_thread(mddev->thread);

		}

		spin_unlock_irq(&mddev->write_lock);

	}

	wait_event(mddev->sb_wait, mddev->sb_dirty==0);

	wait_event(mddev->sb_wait, mddev->flags==0);

}



void md_write_end(mddev_t *mddev)
@@ -5235,7 +5240,6 @@ void md_do_sync(mddev_t *mddev) 
				    !test_bit(In_sync, &rdev->flags) &&

				    rdev->recovery_offset < mddev->curr_resync)

					rdev->recovery_offset = mddev->curr_resync;

			mddev->sb_dirty = 1;

		}

	}
@@ -5292,7 +5296,7 @@ void md_check_recovery(mddev_t *mddev) 
	}



	if ( ! (

		mddev->sb_dirty ||

		mddev->flags ||

		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||

		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||

		(mddev->safemode == 1) ||
@@ -5308,14 +5312,14 @@ void md_check_recovery(mddev_t *mddev) 
		if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&

		    !mddev->in_sync && mddev->recovery_cp == MaxSector) {

			mddev->in_sync = 1;

			mddev->sb_dirty = 3;

			set_bit(MD_CHANGE_CLEAN, &mddev->flags);

		}

		if (mddev->safemode == 1)

			mddev->safemode = 0;

		spin_unlock_irq(&mddev->write_lock);



		if (mddev->sb_dirty)

			md_update_sb(mddev);

		if (mddev->flags)

			md_update_sb(mddev, 0);





		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
@@ -5334,7 +5338,7 @@ void md_check_recovery(mddev_t *mddev) 
				/* activate any spares */

				mddev->pers->spare_active(mddev);

			}

			md_update_sb(mddev);

			md_update_sb(mddev, 1);



			/* if array is no-longer degraded, then any saved_raid_disk

			 * information must be scrapped

drivers/md/multipath.c

+1 −2
Original line number Diff line number Diff line
@@ -253,7 +253,7 @@ static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev) 
			char b[BDEVNAME_SIZE];

			clear_bit(In_sync, &rdev->flags);

			set_bit(Faulty, &rdev->flags);

			mddev->sb_dirty = 1;

			set_bit(MD_CHANGE_DEVS, &mddev->flags);

			conf->working_disks--;

			printk(KERN_ALERT "multipath: IO failure on %s,"

				" disabling IO path. \n	Operation continuing"
@@ -470,7 +470,6 @@ static int multipath_run (mddev_t *mddev) 
	}



	conf->raid_disks = mddev->raid_disks;

	mddev->sb_dirty = 1;

	conf->mddev = mddev;

	spin_lock_init(&conf->device_lock);

	INIT_LIST_HEAD(&conf->retry_list);

drivers/md/raid1.c

+1 −1
Original line number Diff line number Diff line
@@ -969,7 +969,7 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev) 
	}

	clear_bit(In_sync, &rdev->flags);

	set_bit(Faulty, &rdev->flags);

	mddev->sb_dirty = 1;

	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"

		"	Operation continuing on %d devices\n",

		bdevname(rdev->bdev,b), conf->working_disks);

drivers/md/raid10.c

+1 −1
Original line number Diff line number Diff line
@@ -960,7 +960,7 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev) 
	}

	clear_bit(In_sync, &rdev->flags);

	set_bit(Faulty, &rdev->flags);

	mddev->sb_dirty = 1;

	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"

		"	Operation continuing on %d devices\n",

		bdevname(rdev->bdev,b), conf->working_disks);

drivers/md/raid5.c

+4 −4
Original line number Diff line number Diff line
@@ -696,7 +696,7 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev) 
	PRINTK("raid5: error called\n");



	if (!test_bit(Faulty, &rdev->flags)) {

		mddev->sb_dirty = 1;

		set_bit(MD_CHANGE_DEVS, &mddev->flags);

		if (test_bit(In_sync, &rdev->flags)) {

			conf->working_disks--;

			mddev->degraded++;
@@ -2781,9 +2781,9 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped 
		wait_event(conf->wait_for_overlap,

			   atomic_read(&conf->reshape_stripes)==0);

		mddev->reshape_position = conf->expand_progress;

		mddev->sb_dirty = 1;

		set_bit(MD_CHANGE_DEVS, &mddev->flags);

		md_wakeup_thread(mddev->thread);

		wait_event(mddev->sb_wait, mddev->sb_dirty == 0 ||

		wait_event(mddev->sb_wait, mddev->flags == 0 ||

			   kthread_should_stop());

		spin_lock_irq(&conf->device_lock);

		conf->expand_lo = mddev->reshape_position;
@@ -3605,7 +3605,7 @@ static int raid5_start_reshape(mddev_t *mddev) 
	mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices;

	mddev->raid_disks = conf->raid_disks;

	mddev->reshape_position = 0;

	mddev->sb_dirty = 1;

	set_bit(MD_CHANGE_DEVS, &mddev->flags);



	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);

	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);

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